diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..fa1385d
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1 @@
+* -text
diff --git a/source/Properties/AssemblyInfo.cs b/source/Properties/AssemblyInfo.cs
index a35a095..4535dd1 100644
--- a/source/Properties/AssemblyInfo.cs
+++ b/source/Properties/AssemblyInfo.cs
@@ -35,5 +35,5 @@
 // by using the '*' as shown below:
 // [assembly: AssemblyVersion("1.0.*")]
 
-[assembly: AssemblyVersion("2.3.0")]
-[assembly: AssemblyFileVersion("2.3.0")]
\ No newline at end of file
+[assembly: AssemblyVersion("2.4.0")]
+[assembly: AssemblyFileVersion("2.4.0")]
\ No newline at end of file
diff --git a/source/com.esendex.sdk.csproj b/source/com.esendex.sdk.csproj
index bf89fea..991fa79 100644
--- a/source/com.esendex.sdk.csproj
+++ b/source/com.esendex.sdk.csproj
@@ -64,6 +64,7 @@
     <Reference Include="System.Core">
       <RequiredTargetFramework>3.5</RequiredTargetFramework>
     </Reference>
+    <Reference Include="System.Web" />
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
@@ -76,7 +77,6 @@
     <Compile Include="core\CharacterSet.cs" />
     <Compile Include="core\MessageCollection.cs" />
     <Compile Include="core\PagedCollection.cs" />
-    <Compile Include="exceptions\BadRequestException.cs" />
     <Compile Include="extensions\HttpWebResponseExtensions.cs" />
     <Compile Include="http\HttpClient.cs" />
     <Compile Include="http\HttpRequest.cs" />
@@ -85,6 +85,7 @@
     <Compile Include="adapters\HttpWebRequestAdapter.cs" />
     <Compile Include="adapters\HttpWebResponseAdapter.cs" />
     <Compile Include="http\HttpResponseHelper.cs" />
+    <Compile Include="http\HttpUriBuilder.cs" />
     <Compile Include="http\IHttpClient.cs" />
     <Compile Include="adapters\IHttpWebRequestAdapter.cs" />
     <Compile Include="adapters\IHttpWebResponseAdapter.cs" />
@@ -108,6 +109,12 @@
     <Compile Include="messaging\VoiceMessageLanguage.cs" />
     <Compile Include="models\requests\SurveysAddRecipientRequest.cs" />
     <Compile Include="models\requests\SurveysAddRecipientsRequest.cs" />
+    <Compile Include="optouts\models\response\FromAddress.cs" />
+    <Compile Include="optouts\models\response\OptOut.cs" />
+    <Compile Include="optouts\models\response\OptOutCollection.cs" />
+    <Compile Include="optouts\models\request\OptOutCreateRequest.cs" />
+    <Compile Include="optouts\models\response\OptOutCreateResult.cs" />
+    <Compile Include="optouts\OptOutsService.cs" />
     <Compile Include="Properties\BuildInfo.cs" />
     <Compile Include="Request.cs" />
     <Compile Include="rest\resources\ContactsResource.cs" />
@@ -120,8 +127,8 @@
     <Compile Include="rest\resources\ResourceLinkResource.cs" />
     <Compile Include="rest\resources\SessionResource.cs" />
     <Compile Include="sent\FailureReason.cs" />
-    <Compile Include="results\Error.cs" />
-    <Compile Include="results\SurveyResult.cs" />
+    <Compile Include="optouts\models\response\OptOutCreateError.cs" />
+    <Compile Include="surveys\models\SurveyResult.cs" />
     <Compile Include="sent\SentMessage.cs" />
     <Compile Include="messaging\SmsMessage.cs" />
     <Compile Include="messaging\SmsMessageCollection.cs" />
@@ -135,6 +142,7 @@
     <Compile Include="session\ISessionService.cs" />
     <Compile Include="session\EsendexSession.cs" />
     <Compile Include="session\SessionService.cs" />
+    <Compile Include="surveys\models\SurveysAddRecipientError.cs" />
     <Compile Include="surveys\SurveysService.cs" />
     <Compile Include="utilities\ISerialiser.cs" />
     <Compile Include="rest\resources\MessageDispatcherResource.cs" />
@@ -152,9 +160,7 @@
     </None>
     <None Include="packages.config" />
   </ItemGroup>
-  <ItemGroup>
-    <Folder Include="builders\" />
-  </ItemGroup>
+  <ItemGroup />
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.
diff --git a/source/core/PagedCollection.cs b/source/core/PagedCollection.cs
index d51f8ef..5361fda 100644
--- a/source/core/PagedCollection.cs
+++ b/source/core/PagedCollection.cs
@@ -1,86 +1,94 @@
-using System.Collections.Generic;
-using System.Linq;
-using System.Xml.Serialization;
-
-namespace com.esendex.sdk.core
-{
-    /// <summary>
-    /// Represents a paged collection of objects which all paged collection are derived.
-    /// </summary>
-    /// <typeparam name="T">The type of objects.</typeparam>
-    public abstract class PagedCollection<T> : IPagedCollection<T>
-        where T : class
-    {
-        /// <summary>
-        /// <![CDATA[Initialises a new instance of the com.esendex.sdk.core.PagedCollection<T>]]>
-        /// </summary>
-        public PagedCollection()
-        {
-            Items = new List<T>();
-        }
-
-        protected List<T> Items { get; set; }
-
-        private int startIndex;
-
-        /// <summary>
-        /// Gets or sets the page number.
-        /// </summary>
-        [XmlAttribute("startindex")]
-        public int PageNumber
-        {
-            get
-            {
-                // Convert the zero based collection index to a real page number.
-                return (startIndex/PageSize) + 1;
-            }
-            set { startIndex = value; }
-        }
-
-        /// <summary>
-        /// Gets or sets the page size.
-        /// </summary>
-        [XmlAttribute("count")]
-        public int PageSize { get; set; }
-
-        /// <summary>
-        /// Gets or sets the total number of items in the paged resource.
-        /// </summary>
-        [XmlAttribute("totalcount")]
-        public int TotalItems { get; set; }
-
-        /// <summary>
-        /// Determines whether the specified System.Object are considered equal.
-        /// </summary>
-        /// <param name="obj">The System.Object to compare with the current System.Object</param>
-        /// <returns>true if the specified System.Object is equal to the current System.Object; otherwise, false.</returns>
-        public override bool Equals(object obj)
-        {
-            var other = obj as PagedCollection<T>;
-
-            if (other == null) return false;
-
-            if (PageNumber != other.PageNumber) return false;
-            if (PageSize != other.PageSize) return false;
-            if (TotalItems != other.TotalItems) return false;
-
-            if (Items.Count != other.Items.Count) return false;
-
-            for (var i = 0; i < Items.Count; i++)
-            {
-                if (Items.ElementAt(i) != other.Items.ElementAt(i)) return false;
-            }
-
-            return true;
-        }
-
-        /// <summary>
-        /// Serves as a hash function for a particular type.
-        /// </summary>
-        /// <returns>A hash code for the current System.Object</returns>
-        public override int GetHashCode()
-        {
-            return base.GetHashCode();
-        }
-    }
+using System.Collections.Generic;
+using System.Linq;
+using System.Xml.Serialization;
+using Newtonsoft.Json;
+
+namespace com.esendex.sdk.core
+{
+    /// <summary>
+    /// Represents a paged collection of objects which all paged collection are derived.
+    /// </summary>
+    /// <typeparam name="T">The type of objects.</typeparam>
+    public abstract class PagedCollection<T> : IPagedCollection<T>
+        where T : class
+    {
+        /// <summary>
+        /// <![CDATA[Initialises a new instance of the com.esendex.sdk.core.PagedCollection<T>]]>
+        /// </summary>
+        public PagedCollection()
+        {
+            Items = new List<T>();
+        }
+
+        protected List<T> Items { get; set; }
+
+        private int startIndex;
+
+        /// <summary>
+        /// Gets or sets the page number.
+        /// </summary>
+        [XmlAttribute("startindex")]
+        [JsonProperty("startindex")]
+        public int PageNumber
+        {
+            get
+            {
+                // Convert the zero based collection index to a real page number.
+                if (PageSize == 0 && TotalItems == 0)
+                {
+                    return 1;
+                }
+                return (startIndex/PageSize) + 1;
+            }
+            set { startIndex = value; }
+        }
+
+        /// <summary>
+        /// Gets or sets the page size.
+        /// </summary>
+        [XmlAttribute("count")]
+        [JsonProperty("count")]
+        public int PageSize { get; set; }
+
+        /// <summary>
+        /// Gets or sets the total number of items in the paged resource.
+        /// </summary>
+        [XmlAttribute("totalcount")]
+        [JsonProperty("totalcount")]
+        public int TotalItems { get; set; }
+
+        /// <summary>
+        /// Determines whether the specified System.Object are considered equal.
+        /// </summary>
+        /// <param name="obj">The System.Object to compare with the current System.Object</param>
+        /// <returns>true if the specified System.Object is equal to the current System.Object; otherwise, false.</returns>
+        public override bool Equals(object obj)
+        {
+            var other = obj as PagedCollection<T>;
+
+            if (other == null) return false;
+
+            if (PageNumber != other.PageNumber) return false;
+            if (PageSize != other.PageSize) return false;
+            if (TotalItems != other.TotalItems) return false;
+
+            if (Items.Count != other.Items.Count) return false;
+
+            for (var i = 0; i < Items.Count; i++)
+            {
+                if (Items.ElementAt(i) != other.Items.ElementAt(i)) return false;
+            }
+
+            return true;
+        }
+
+        /// <summary>
+        /// Serves as a hash function for a particular type.
+        /// </summary>
+        /// <returns>A hash code for the current System.Object</returns>
+        public override int GetHashCode()
+        {
+            return base.GetHashCode();
+        }
+    }
 }
\ No newline at end of file
diff --git a/source/exceptions/BadRequestException.cs b/source/exceptions/BadRequestException.cs
deleted file mode 100644
index e8e85a3..0000000
--- a/source/exceptions/BadRequestException.cs
+++ /dev/null
@@ -1,16 +0,0 @@
-using System.Net;
-using com.esendex.sdk.results;
-
-namespace com.esendex.sdk.exceptions
-{
-    public class BadRequestException : WebException
-    {
-        public BadRequestException(WebException webException, Error[] errors) 
-            : base(webException.Message, webException.InnerException, webException.Status, webException.Response)
-        {
-            Errors = errors;
-        }
-
-        public Error[] Errors { get; private set; }
-    }
-}
\ No newline at end of file
diff --git a/source/extensions/HttpWebResponseExtensions.cs b/source/extensions/HttpWebResponseExtensions.cs
index 177a55a..21373e6 100644
--- a/source/extensions/HttpWebResponseExtensions.cs
+++ b/source/extensions/HttpWebResponseExtensions.cs
@@ -9,6 +9,7 @@ internal static class HttpWebResponseExtensions
         public static T DeserialiseJson<T>(this HttpWebResponse response)
         {
             var serializer = new JsonSerializer();
+
             using (var sr = new StreamReader(response.GetResponseStream()))
             using (var jsonTextReader = new JsonTextReader(sr))
             {
diff --git a/source/http/HttpUriBuilder.cs b/source/http/HttpUriBuilder.cs
new file mode 100644
index 0000000..6f31fe0
--- /dev/null
+++ b/source/http/HttpUriBuilder.cs
@@ -0,0 +1,35 @@
+using System;
+using System.Collections.Specialized;
+using System.Web;
+
+namespace com.esendex.sdk.http
+{
+    public class HttpUriBuilder
+    {
+        private readonly UriBuilder _uriBuilder;
+        private readonly NameValueCollection _query;
+
+        private HttpUriBuilder(string url)
+        {
+            _uriBuilder = new UriBuilder(url);
+            _query = HttpUtility.ParseQueryString(string.Empty);
+        }
+
+        public static HttpUriBuilder Create(string url)
+        {
+            return new HttpUriBuilder(url);
+        }
+
+        public HttpUriBuilder WithParameter(string name, string value)
+        {
+            _query[name] = value;
+            return this;
+        }
+
+        public Uri Build()
+        {
+            _uriBuilder.Query = _query.ToString();
+            return _uriBuilder.Uri;
+        }
+    }
+}
\ No newline at end of file
diff --git a/source/optouts/OptOutsService.cs b/source/optouts/OptOutsService.cs
new file mode 100644
index 0000000..90cd605
--- /dev/null
+++ b/source/optouts/OptOutsService.cs
@@ -0,0 +1,192 @@
+using System;
+using System.Net;
+using com.esendex.sdk.extensions;
+using com.esendex.sdk.http;
+using com.esendex.sdk.optouts.models.request;
+using com.esendex.sdk.optouts.models.response;
+using Newtonsoft.Json;
+
+namespace com.esendex.sdk.optouts
+{
+    /// <summary>
+    /// A service to create and retrieve opt outs.
+    /// </summary>
+    public class OptOutsService
+    {
+        private const string BASE_URL = "https://api.esendex.com";
+
+        private readonly Uri _baseUrl;
+        private readonly EsendexCredentials _credentials;
+
+        internal OptOutsService(string url, EsendexCredentials esendexCredentials)
+        {
+            _baseUrl = new Uri(url);
+            _credentials = esendexCredentials;
+        }
+
+        /// <summary>
+        /// Initialises a new instance of the InboxService
+        /// </summary>
+        /// <param name="credentials">A com.esendex.sdk.EsendexCredentials instance containing your username and password.</param>
+        public OptOutsService(EsendexCredentials credentials) : this(BASE_URL, credentials)
+        {
+        }
+
+        /// <summary>
+        /// Initialises a new instance of the InboxService
+        /// </summary>
+        /// <param name="username">A string containing your username.</param>
+        /// <param name="password">A string containing your password.</param>
+        public OptOutsService(string username, string password) : this(BASE_URL, new EsendexCredentials(username, password))
+        {
+        }
+
+        /// <summary>
+        /// Gets a com.esendex.sdk.optouts.OptOut instance containing an opt out.
+        /// </summary>
+        /// <param name="id">A System.Guid instance that contains the Id of an opt out.</param>
+        /// <returns>A com.esendex.sdk.optouts.OptOut instance containing an opt out.</returns>
+        /// <exception cref="System.Net.WebException"></exception>
+        public OptOut GetById(Guid optOutId)
+        {
+            var requestUrl = new Uri(_baseUrl, string.Format("v1.0/optouts/{0}", optOutId));
+            var request = Request.Create("GET", requestUrl)
+                                 .WithHeader("Authorization", "Basic " + _credentials.EncodedValue())
+                                 .WithAcceptHeader(Constants.JSON_MEDIA_TYPE)
+                                 .If(_credentials.UseProxy, r => r.WithProxy(_credentials.WebProxy));
+
+            var response = request.GetResponse();
+            return response.DeserialiseJson<OptOut>();
+        }
+
+        /// <summary>
+        /// Gets a com.esendex.sdk.optouts.OptOutCollection instance containing a collection of com.esendex.sdk.optouts.OptOut.
+        /// </summary>
+        /// <param name="phoneNumber">A string that contains the phone number to search with.</param>
+        /// <param name="accountReference">A string that contains the account reference to search with.</param>
+        /// <param name="pageNumber">An int that that specifies which page of results to return.</param>
+        /// <param name="pageSize">An int that specifies how many results to return in a page.</param>
+        /// <returns>A com.esendex.sdk.optouts.OptOutCollection instance containing a collection of com.esendex.sdk.optouts.OptOut.</returns>
+        /// <exception cref="System.Net.WebException"></exception>
+        public OptOutCollection GetByPhoneNumber(string phoneNumber, string accountReference, int pageNumber, int pageSize)
+        {
+            var uri = BuildGetAllUri(phoneNumber, accountReference, pageNumber, pageSize);
+
+            var request = Request.Create("GET", uri)
+                                 .WithHeader("Authorization", "Basic " + _credentials.EncodedValue())
+                                 .WithAcceptHeader(Constants.JSON_MEDIA_TYPE)
+                                 .If(_credentials.UseProxy, r => r.WithProxy(_credentials.WebProxy));
+
+            var response = request.GetResponse();
+            return response.DeserialiseJson<OptOutCollection>();
+        }
+
+        private Uri BuildGetAllUri(string phoneNumber, string accountReference, int pageNumber, int pageSize)
+        {
+            var requestUrl = _baseUrl + "v1.0/optouts";
+
+            var builder = HttpUriBuilder.Create(requestUrl)
+                                        .WithParameter("startIndex", GetStartIndex(pageNumber, pageSize).ToString())
+                                        .WithParameter("count", pageSize.ToString());
+
+            if (accountReference != null)
+            {
+                builder.WithParameter("accountreference", accountReference);
+            }
+
+            if (phoneNumber != null)
+            {
+                builder.WithParameter("from", phoneNumber);
+            }
+
+            return builder.Build();
+        }
+
+        /// <summary>
+        /// Gets a com.esendex.sdk.optouts.OptOutCollection instance containing a collection of com.esendex.sdk.optouts.OptOut.
+        /// </summary>
+        /// <param name="phoneNumber">A string that contains the phone number to search with.</param>
+        /// <param name="pageNumber">An int that that specifies which page of results to return.</param>
+        /// <param name="pageSize">An int that specifies how many results to return in a page.</param>
+        /// <returns>A com.esendex.sdk.optouts.OptOutCollection instance containing a collection of com.esendex.sdk.optouts.OptOut.</returns>
+        /// <exception cref="System.Net.WebException"></exception>
+        public OptOutCollection GetByFromAddress(string from, int pageNumber, int pageSize)
+        {
+            return GetByPhoneNumber(from, null, pageNumber, pageSize);
+        }
+
+        /// <summary>
+        /// Gets a com.esendex.sdk.optouts.OptOutCollection instance containing a collection of com.esendex.sdk.optouts.OptOut.
+        /// </summary>
+        /// <param name="accountReference">A string that contains the account reference to search with.</param>
+        /// <param name="pageNumber">An int that that specifies which page of results to return.</param>
+        /// <param name="pageSize">An int that specifies how many results to return in a page.</param>
+        /// <returns>A com.esendex.sdk.optouts.OptOutCollection instance containing a collection of com.esendex.sdk.optouts.OptOut.</returns>
+        /// <exception cref="System.Net.WebException"></exception>
+        public OptOutCollection GetByAccountReference(string accountReference, int pageNumber, int pageSize)
+        {
+            return GetByPhoneNumber(null, accountReference, pageNumber, pageSize);
+        }
+
+        /// <summary>
+        /// Gets a com.esendex.sdk.optouts.OptOutCollection instance containing a collection of com.esendex.sdk.optouts.OptOut.
+        /// </summary>
+        /// <param name="pageNumber">An int that that specifies which page of results to return.</param>
+        /// <param name="pageSize">An int that specifies how many results to return in a page.</param>
+        /// <returns>A com.esendex.sdk.optouts.OptOutCollection instance containing a collection of com.esendex.sdk.optouts.OptOut.</returns>
+        /// <exception cref="System.Net.WebException"></exception>
+        public OptOutCollection GetAll(int pageNumber, int pageSize)
+        {
+            return GetByPhoneNumber(null, null, pageNumber, pageSize);
+        }
+
+        private int GetStartIndex(int pageNumber, int pageSize)
+        {
+            if (pageNumber < 1) throw new ArgumentException("Page number must be greater than zero.", "pageNumber");
+            if (pageSize < 1) throw new ArgumentException("Page size must be greater than zero.", "pageSize");
+
+            var startIndex = (pageNumber - 1) * pageSize;
+            return startIndex;
+        }
+
+        /// <summary>
+        /// Gets a com.esendex.sdk.optouts.OptOutCreateResult instance containing an opt out.
+        /// </summary>
+        /// <param name="phoneNumber">A string that contains the phone number to be opted out.</param>
+        /// <param name="accountReference">A string that contains the account reference to which the opt out will be applied.</param>
+        /// <returns>A com.esendex.sdk.optouts.OptOutCreateResult instance containing the created opt out.</returns>
+        /// <exception cref="System.Net.WebException"></exception>
+        public OptOutCreateResult Add(string accountReference, string phoneNumber)
+        {
+            var requestData = new OptOutCreateRequest
+            {
+                AccountReference = accountReference,
+                From = new FromAddress
+                {
+                    PhoneNumber = phoneNumber
+                }
+            };
+
+            var requestUrl = new Uri(string.Concat(_baseUrl, "v1.0/optouts"));
+            var request = Request.Create("POST", requestUrl)
+                                 .WithHeader("Authorization", "Basic " + _credentials.EncodedValue())
+                                 .WithAcceptHeader(Constants.JSON_MEDIA_TYPE)
+                                 .If(_credentials.UseProxy, r => r.WithProxy(_credentials.WebProxy))
+                                 .WriteBody(Constants.JSON_MEDIA_TYPE, streamWriter => JsonSerializer.Create().Serialize(streamWriter, requestData));
+
+            HttpWebResponse response;
+            try
+            {
+                response = request.GetResponse();
+            }
+            catch (WebException ex)
+            {
+                response = (HttpWebResponse)ex.Response;
+                if (response.StatusCode != HttpStatusCode.BadRequest)
+                    throw;
+            }
+
+            return response.DeserialiseJson<OptOutCreateResult>();
+        }
+    }
+}
\ No newline at end of file
diff --git a/source/optouts/models/request/OptOutCreateRequest.cs b/source/optouts/models/request/OptOutCreateRequest.cs
new file mode 100644
index 0000000..7da6293
--- /dev/null
+++ b/source/optouts/models/request/OptOutCreateRequest.cs
@@ -0,0 +1,10 @@
+using com.esendex.sdk.optouts.models.response;
+
+namespace com.esendex.sdk.optouts.models.request
+{
+    public class OptOutCreateRequest
+    {
+        public string AccountReference { get; set; }
+        public FromAddress From { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/source/optouts/models/response/FromAddress.cs b/source/optouts/models/response/FromAddress.cs
new file mode 100644
index 0000000..84ad082
--- /dev/null
+++ b/source/optouts/models/response/FromAddress.cs
@@ -0,0 +1,13 @@
+namespace com.esendex.sdk.optouts.models.response
+{
+    /// <summary>
+    /// Represents an address for an opt out
+    /// </summary>
+    public class FromAddress
+    {
+        /// <summary>
+        /// <![CDATA[A System.String instance that contains the address.]]>
+        /// </summary>
+        public string PhoneNumber { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/source/optouts/models/response/OptOut.cs b/source/optouts/models/response/OptOut.cs
new file mode 100644
index 0000000..51705a3
--- /dev/null
+++ b/source/optouts/models/response/OptOut.cs
@@ -0,0 +1,30 @@
+using System;
+
+namespace com.esendex.sdk.optouts.models.response
+{
+    /// <summary>
+    /// Represents an opt out
+    /// </summary>
+    public class OptOut
+    {
+        /// <summary>
+        /// <![CDATA[A System.Guid instance that identifies the opt out.]]>
+        /// </summary>
+        public Guid Id { get; set; }
+
+        /// <summary>
+        /// <![CDATA[A System.DateTime instance that indicates when the opt out was created.]]>
+        /// </summary>
+        public DateTime ReceivedAt { get; set; }
+
+        /// <summary>
+        /// <![CDATA[A System.String instance that indicates the account the opt out belongs to.]]>
+        /// </summary>
+        public string AccountReference { get; set; }
+
+        /// <summary>
+        /// <![CDATA[A com.esendex.sdk.optouts.models.response.FromAddress instance that represents the address of the opt out.]]>
+        /// </summary>
+        public FromAddress From { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/source/optouts/models/response/OptOutCollection.cs b/source/optouts/models/response/OptOutCollection.cs
new file mode 100644
index 0000000..858434f
--- /dev/null
+++ b/source/optouts/models/response/OptOutCollection.cs
@@ -0,0 +1,20 @@
+using System.Collections.Generic;
+using com.esendex.sdk.core;
+
+namespace com.esendex.sdk.optouts.models.response
+{
+    /// <summary>
+    /// Represents a collection of Opt Outs
+    /// </summary>
+    public class OptOutCollection : PagedCollection<OptOut>
+    {
+        /// <summary>
+        /// <![CDATA[A System.Collections.Generic.List<OptOut> instance that contains the optouts.]]>
+        /// </summary>
+        public List<OptOut> OptOuts
+        {
+            get { return Items; }
+            set { Items = value; }
+        }
+    }
+}
\ No newline at end of file
diff --git a/source/optouts/models/response/OptOutCreateError.cs b/source/optouts/models/response/OptOutCreateError.cs
new file mode 100644
index 0000000..4f7842f
--- /dev/null
+++ b/source/optouts/models/response/OptOutCreateError.cs
@@ -0,0 +1,18 @@
+namespace com.esendex.sdk.optouts.models.response
+{
+    /// <summary>
+    /// Holds information related to a bad request response when creating a new opt out
+    /// </summary>
+    public class OptOutCreateError
+    {
+        /// <summary>
+        /// <![CDATA[A System.String instance that contains the code indicating the failure reason.]]>
+        /// </summary>
+        public string Code { get; set; }
+
+        /// <summary>
+        /// <![CDATA[A System.String instance that contains a human readable description of the failure reason.]]>
+        /// </summary>
+        public string Description { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/source/optouts/models/response/OptOutCreateResult.cs b/source/optouts/models/response/OptOutCreateResult.cs
new file mode 100644
index 0000000..5e8d930
--- /dev/null
+++ b/source/optouts/models/response/OptOutCreateResult.cs
@@ -0,0 +1,26 @@
+namespace com.esendex.sdk.optouts.models.response
+{
+    /// <summary>
+    /// Represents the result of attempting to creat a new opt out
+    /// </summary>
+    public class OptOutCreateResult
+    {
+        /// <summary>
+        /// <![CDATA[Initialises a new instance of the com.esendex.sdk.optouts.models.response.OptOutCreateResult<T>]]>
+        /// </summary>
+        public OptOutCreateResult()
+        {
+            Errors = new OptOutCreateError[0];
+        }
+
+        /// <summary>
+        /// <![CDATA[A com.esendex.sdk.optouts.models.response.OptOut instance that contains the created opt out if it was successful.]]>
+        /// </summary>
+        public OptOut OptOut { get; set; }
+
+        /// <summary>
+        /// <![CDATA[A com.esendex.sdk.optouts.models.response.OptOutCreateError instance that contains errors associated with a failed attempt.]]>
+        /// </summary>
+        public OptOutCreateError[] Errors { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/source/results/SurveyResult.cs b/source/results/SurveyResult.cs
deleted file mode 100644
index fbc9130..0000000
--- a/source/results/SurveyResult.cs
+++ /dev/null
@@ -1,7 +0,0 @@
-namespace com.esendex.sdk.results
-{
-    public class SurveyResult
-    {
-        public Error[] Errors { get; set; }
-    }
-}
\ No newline at end of file
diff --git a/source/surveys/SurveysService.cs b/source/surveys/SurveysService.cs
index dae171e..cb97f1d 100644
--- a/source/surveys/SurveysService.cs
+++ b/source/surveys/SurveysService.cs
@@ -1,11 +1,9 @@
 using System;
 using System.Collections.Generic;
-using System.IO;
 using System.Net;
-using com.esendex.sdk.exceptions;
 using com.esendex.sdk.extensions;
 using com.esendex.sdk.models.requests;
-using com.esendex.sdk.results;
+using com.esendex.sdk.surveys.models;
 using Newtonsoft.Json;
 
 namespace com.esendex.sdk.surveys
@@ -47,20 +45,19 @@ public SurveyResult Send(Guid surveyId, string recipient, Dictionary<string, str
                                  .If(_credentials.UseProxy, r => r.WithProxy(_credentials.WebProxy))
                                  .WriteBody(Constants.JSON_MEDIA_TYPE, streamWriter => JsonSerializer.Create().Serialize(streamWriter, requestData));
 
+            HttpWebResponse response;
             try
             {
-                request.GetResponse();
+                response = request.GetResponse();
             }
             catch (WebException ex)
             {
-                var response = (HttpWebResponse) ex.Response;
+                response = (HttpWebResponse) ex.Response;
                 if (response.StatusCode != HttpStatusCode.BadRequest)
                     throw;
-
-                throw new BadRequestException(ex, response.DeserialiseJson<SurveyResult>().Errors);
             }
 
-            return new SurveyResult();
+            return response.DeserialiseJson<SurveyResult>();
         }
     }
 }
\ No newline at end of file
diff --git a/source/surveys/models/SurveyResult.cs b/source/surveys/models/SurveyResult.cs
new file mode 100644
index 0000000..90476ee
--- /dev/null
+++ b/source/surveys/models/SurveyResult.cs
@@ -0,0 +1,7 @@
+namespace com.esendex.sdk.surveys.models
+{
+    public class SurveyResult
+    {
+        public SurveysAddRecipientError[] Errors { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/source/results/Error.cs b/source/surveys/models/SurveysAddRecipientError.cs
similarity index 62%
rename from source/results/Error.cs
rename to source/surveys/models/SurveysAddRecipientError.cs
index ec86a83..e83b5cb 100644
--- a/source/results/Error.cs
+++ b/source/surveys/models/SurveysAddRecipientError.cs
@@ -1,6 +1,6 @@
-namespace com.esendex.sdk.results
+namespace com.esendex.sdk.surveys.models
 {
-    public class Error
+    public class SurveysAddRecipientError
     {
         public string Code { get; set; }
         public string Description { get; set; }
diff --git a/test/com.esendex.sdk.test.csproj b/test/com.esendex.sdk.test.csproj
index 307d5a6..838bac9 100644
--- a/test/com.esendex.sdk.test.csproj
+++ b/test/com.esendex.sdk.test.csproj
@@ -108,8 +108,21 @@
     <Compile Include="messaging\SmsMessageSerializationTests.cs" />
     <Compile Include="mockapi\MockApi.cs" />
     <Compile Include="mockapi\MockEndpoint.cs" />
-    <Compile Include="models\requests\SurveyAddRecipientRequest.cs" />
-    <Compile Include="models\requests\SurveyAddRecipientsRequest.cs" />
+    <Compile Include="models\requests\optouts\From.cs" />
+    <Compile Include="models\requests\optouts\OptOutsAddRequest.cs" />
+    <Compile Include="models\requests\surveys\SurveyAddRecipientRequest.cs" />
+    <Compile Include="models\requests\surveys\SurveyAddRecipientsRequest.cs" />
+    <Compile Include="optouts\add\OptOutsServiceAddTests.cs" />
+    <Compile Include="optouts\add\OptOutsServiceAddWithErrorTests.cs" />
+    <Compile Include="optouts\add\OptOutsServiceAddWithStructuredErrorTests.cs" />
+    <Compile Include="optouts\getall\OptOutsServiceGetAllTests.cs" />
+    <Compile Include="optouts\getall\OptOutsServiceGetAllWithAccountReferenceTests.cs" />
+    <Compile Include="optouts\getall\OptOutsServiceGetAllWithErrorTests.cs" />
+    <Compile Include="optouts\getall\OptOutsServiceGetAllWithFromAndAccountReferenceTests.cs" />
+    <Compile Include="optouts\getall\OptOutsServiceGetAllWithFromTests.cs" />
+    <Compile Include="optouts\getall\OptOutsServiceGetAllWithNoResultsTests.cs" />
+    <Compile Include="optouts\getbyid\OptOutsServiceGetByIdTests.cs" />
+    <Compile Include="optouts\getbyid\OptOutsServiceGetByIdWithErrorResponseTests.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="rest\resources\ContactsResourceTests.cs" />
     <Compile Include="rest\resources\InboxMessagesResourceTests.cs" />
diff --git a/test/models/requests/optouts/From.cs b/test/models/requests/optouts/From.cs
new file mode 100644
index 0000000..e7b0ea4
--- /dev/null
+++ b/test/models/requests/optouts/From.cs
@@ -0,0 +1,7 @@
+namespace com.esendex.sdk.test.models.requests.optouts
+{
+    public class From
+    {
+        public string PhoneNumber { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/test/models/requests/optouts/OptOutsAddRequest.cs b/test/models/requests/optouts/OptOutsAddRequest.cs
new file mode 100644
index 0000000..0fb7b3d
--- /dev/null
+++ b/test/models/requests/optouts/OptOutsAddRequest.cs
@@ -0,0 +1,8 @@
+namespace com.esendex.sdk.test.models.requests.optouts
+{
+    public class OptOutsAddRequest
+    {
+        public string AccountReference { get; set; }
+        public From From { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/test/models/requests/SurveyAddRecipientRequest.cs b/test/models/requests/surveys/SurveyAddRecipientRequest.cs
similarity index 82%
rename from test/models/requests/SurveyAddRecipientRequest.cs
rename to test/models/requests/surveys/SurveyAddRecipientRequest.cs
index 16076e8..fedbc32 100644
--- a/test/models/requests/SurveyAddRecipientRequest.cs
+++ b/test/models/requests/surveys/SurveyAddRecipientRequest.cs
@@ -1,7 +1,7 @@
 using System.Collections.Generic;
 using Newtonsoft.Json;
 
-namespace com.esendex.sdk.test.models.requests
+namespace com.esendex.sdk.test.models.requests.surveys
 {
     public class SurveyAddRecipientRequest
     {
diff --git a/test/models/requests/SurveyAddRecipientsRequest.cs b/test/models/requests/surveys/SurveyAddRecipientsRequest.cs
similarity index 77%
rename from test/models/requests/SurveyAddRecipientsRequest.cs
rename to test/models/requests/surveys/SurveyAddRecipientsRequest.cs
index de8085d..cae8b17 100644
--- a/test/models/requests/SurveyAddRecipientsRequest.cs
+++ b/test/models/requests/surveys/SurveyAddRecipientsRequest.cs
@@ -1,7 +1,7 @@
 using System.Collections.Generic;
 using Newtonsoft.Json;
 
-namespace com.esendex.sdk.test.models.requests
+namespace com.esendex.sdk.test.models.requests.surveys
 {
     public class SurveyAddRecipientsRequest
     {
diff --git a/test/optouts/add/OptOutsServiceAddTests.cs b/test/optouts/add/OptOutsServiceAddTests.cs
new file mode 100644
index 0000000..b520019
--- /dev/null
+++ b/test/optouts/add/OptOutsServiceAddTests.cs
@@ -0,0 +1,93 @@
+using System;
+using System.Reflection;
+using com.esendex.sdk.optouts;
+using com.esendex.sdk.optouts.models.response;
+using com.esendex.sdk.test.mockapi;
+using com.esendex.sdk.test.models.requests.optouts;
+using Newtonsoft.Json;
+using NUnit.Framework;
+
+namespace com.esendex.sdk.test.optouts.add
+{
+    [TestFixture]
+    public class OptOutsServiceAddTests
+    {
+        private readonly Version _version = Assembly.GetAssembly(typeof (OptOutsService)).GetName().Version;
+        private mockapi.Request _request;
+        private OptOutCreateResult _result;
+        private string _phoneNumber;
+        private string _accountReference;
+        private Guid _optOutId;
+        private DateTime _receivedAt;
+
+        [TestFixtureSetUp]
+        public void Given()
+        {
+            const string username = "user@example.com";
+            const string password = "heythiscantbeguessed";
+
+            _optOutId = Guid.NewGuid();
+            _accountReference = "EX0123456";
+            _receivedAt = DateTime.UtcNow;
+            _phoneNumber = "44123456789";
+
+            var data = new
+            {
+                OptOut = new
+                {
+                    Id = _optOutId,
+                    ReceivedAt = _receivedAt,
+                    AccountReference = _accountReference,
+                    From = new
+                    {
+                        PhoneNumber = _phoneNumber
+                    }
+                }
+            };
+
+            MockApi.SetEndpoint(new MockEndpoint(200, JsonConvert.SerializeObject(data), "application/json; charset=utf-8"));
+
+            var optOutClient = new OptOutsService(MockApi.Url, new EsendexCredentials(username, password));
+
+            _result = optOutClient.Add(_accountReference, _phoneNumber);
+            _request = MockApi.LastRequest;
+        }
+
+        [Test]
+        public void ThenTheExpectedRequestIsMade()
+        {
+            Assert.That(_request.Method, Is.EqualTo("POST"));
+            Assert.That(_request.Url, Is.EqualTo("/v1.0/optouts"));
+        }
+
+        [Test]
+        public void ThenTheRequestHasTheExpectedHeaders()
+        {
+            var expectedUserAgent = string.Format("Esendex .NET SDK v{0}.{1}.{2}", _version.Major, _version.Minor, _version.Build);
+            Assert.That(_request.Headers["User-Agent"], Is.EqualTo(expectedUserAgent));
+
+            Assert.That(_request.Headers["Accept"], Is.EqualTo("application/json; charset=utf-8"));
+            Assert.That(_request.Headers["Authorization"], Is.EqualTo("Basic dXNlckBleGFtcGxlLmNvbTpoZXl0aGlzY2FudGJlZ3Vlc3NlZA=="));
+        }
+
+        [Test]
+        public void ThenTheCorrectRequestIsSent()
+        {
+            var request = JsonConvert.DeserializeObject<OptOutsAddRequest>(_request.Body);
+
+            Assert.That(request.AccountReference, Is.EqualTo(_accountReference));
+            Assert.That(request.From.PhoneNumber, Is.EqualTo(_phoneNumber));
+        }
+
+        [Test]
+        public void ThenTheExpectedResultIsReturned()
+        {
+            Assert.That(_result.OptOut.Id, Is.EqualTo(_optOutId));
+            Assert.That(_result.OptOut.AccountReference, Is.EqualTo(_accountReference));
+            Assert.That(_result.OptOut.ReceivedAt, Is.EqualTo(_receivedAt).Within(1).Seconds);
+            Assert.That(_result.OptOut.From.PhoneNumber, Is.EqualTo(_phoneNumber));
+
+            Assert.That(_result.Errors.Length, Is.EqualTo(0));
+        }
+    }
+}
\ No newline at end of file
diff --git a/test/optouts/add/OptOutsServiceAddWithErrorTests.cs b/test/optouts/add/OptOutsServiceAddWithErrorTests.cs
new file mode 100644
index 0000000..0f4cf88
--- /dev/null
+++ b/test/optouts/add/OptOutsServiceAddWithErrorTests.cs
@@ -0,0 +1,50 @@
+using System.Net;
+using com.esendex.sdk.optouts;
+using com.esendex.sdk.test.mockapi;
+using NUnit.Framework;
+
+namespace com.esendex.sdk.test.optouts.add
+{
+    [TestFixture(403, HttpStatusCode.Forbidden)]
+    [TestFixture(409, HttpStatusCode.Conflict)]
+    [TestFixture(500, HttpStatusCode.InternalServerError)]
+    public class OptOutsServiceAddWithErrorTests
+    {
+        private WebException _result;
+        private readonly int _statusCode;
+        private readonly HttpStatusCode _expectedCode;
+
+        public OptOutsServiceAddWithErrorTests(int statusCode, HttpStatusCode expectedCode)
+        {
+            _statusCode = statusCode;
+            _expectedCode = expectedCode;
+        }
+
+        [TestFixtureSetUp]
+        public void Given()
+        {
+            const string username = "user@example.com";
+            const string password = "heythiscantbeguessed";
+
+            MockApi.SetEndpoint(new MockEndpoint(_statusCode));
+
+            var optOutClient = new OptOutsService(MockApi.Url, new EsendexCredentials(username, password));
+
+            try
+            {
+                optOutClient.Add("something", "somethingelse");
+            }
+            catch (WebException ex)
+            {
+                _result = ex;
+            }
+        }
+
+        [Test]
+        public void ThenTheErrorIsReturned()
+        {
+            var webResponse = (HttpWebResponse) _result.Response;
+            Assert.That(webResponse.StatusCode, Is.EqualTo(_expectedCode));
+        }
+    }
+}
\ No newline at end of file
diff --git a/test/optouts/add/OptOutsServiceAddWithStructuredErrorTests.cs b/test/optouts/add/OptOutsServiceAddWithStructuredErrorTests.cs
new file mode 100644
index 0000000..556a211
--- /dev/null
+++ b/test/optouts/add/OptOutsServiceAddWithStructuredErrorTests.cs
@@ -0,0 +1,52 @@
+using System.Linq;
+using com.esendex.sdk.optouts;
+using com.esendex.sdk.optouts.models.response;
+using com.esendex.sdk.test.mockapi;
+using Newtonsoft.Json;
+using NUnit.Framework;
+
+namespace com.esendex.sdk.test.optouts.add
+{
+    [TestFixture]
+    public class OptOutsServiceAddWithStructuredErrorTests
+    {
+        private OptOutCreateResult _result;
+        private string _code = "phonenumber_missing";
+        private string _description = "Phone number is missing";
+
+        [TestFixtureSetUp]
+        public void Given()
+        {
+            const string username = "user@example.com";
+            const string password = "heythiscantbeguessed";
+
+            var data = new
+            {
+                Errors = new[]
+                {
+                    new
+                    {
+                        Code = _code,
+                        Description = _description
+                    }
+                }
+            };
+
+            MockApi.SetEndpoint(new MockEndpoint(400, JsonConvert.SerializeObject(data), "application/json"));
+
+            var optOutClient = new OptOutsService(MockApi.Url, new EsendexCredentials(username, password));
+
+            _result = optOutClient.Add("", "");
+        }
+
+        [Test]
+        public void ThenTheStructuredErrorIsReturned()
+        {
+            Assert.That(_result.Errors.Length, Is.EqualTo(1));
+            Assert.That(_result.Errors.First().Code, Is.EqualTo(_code));
+            Assert.That(_result.Errors.First().Description, Is.EqualTo(_description));
+
+            Assert.That(_result.OptOut, Is.Null);
+        }
+    }
+}
\ No newline at end of file
diff --git a/test/optouts/getall/OptOutsServiceGetAllTests.cs b/test/optouts/getall/OptOutsServiceGetAllTests.cs
new file mode 100644
index 0000000..7b08829
--- /dev/null
+++ b/test/optouts/getall/OptOutsServiceGetAllTests.cs
@@ -0,0 +1,97 @@
+using System;
+using System.Linq;
+using System.Reflection;
+using com.esendex.sdk.optouts;
+using com.esendex.sdk.optouts.models.response;
+using com.esendex.sdk.test.mockapi;
+using Newtonsoft.Json;
+using NUnit.Framework;
+
+namespace com.esendex.sdk.test.optouts.getall
+{
+    [TestFixture]
+    public class OptOutsServiceGetAllTests
+    {
+        private readonly Version _version = Assembly.GetAssembly(typeof(OptOutsService)).GetName().Version;
+        private mockapi.Request _request;
+        private OptOutCollection _result;
+        private string _phoneNumber;
+        private string _accountReference;
+        private int _pageSize;
+        private int _pageNumber;
+        private Guid _optOutId;
+        private DateTime _receivedAt;
+
+        [TestFixtureSetUp]
+        public void Given()
+        {
+            const string username = "user@example.com";
+            const string password = "heythiscantbeguessed";
+
+            _pageSize = 15;
+            _pageNumber = 1;
+
+            _optOutId = Guid.NewGuid();
+            _receivedAt = DateTime.UtcNow;
+            _accountReference = "EX0123456";
+            _phoneNumber = "44123456789";
+
+            var data = new
+            {
+                OptOuts = new[]
+                {
+                    new
+                    {
+                        Id = _optOutId,
+                        ReceivedAt = _receivedAt,
+                        AccountReference = _accountReference,
+                        From = new { PhoneNumber = _phoneNumber },
+                     }
+                },
+                StartIndex = 0,
+                Count = 1,
+                TotalCount = 1
+            };
+
+            MockApi.SetEndpoint(new MockEndpoint(200, JsonConvert.SerializeObject(data), "application/json"));
+
+            var optOutClient = new OptOutsService(MockApi.Url, new EsendexCredentials(username, password));
+
+            _result = optOutClient.GetAll(_pageNumber, _pageSize);
+            _request = MockApi.LastRequest;
+        }
+
+        [Test]
+        public void ThenTheExpectedRequestIsMade()
+        {
+            var expectedUrl = string.Format("/v1.0/optouts?startIndex={0}&count={1}", (_pageNumber - 1) * _pageSize, _pageSize);
+
+            Assert.That(_request.Method, Is.EqualTo("GET"));
+            Assert.That(_request.Url, Is.EqualTo(expectedUrl));
+        }
+
+        [Test]
+        public void ThenTheRequestHasTheExpectedHeaders()
+        {
+            var expectedUserAgent = string.Format("Esendex .NET SDK v{0}.{1}.{2}", _version.Major, _version.Minor, _version.Build);
+            Assert.That(_request.Headers["User-Agent"], Is.EqualTo(expectedUserAgent));
+
+            Assert.That(_request.Headers["Accept"], Is.EqualTo("application/json; charset=utf-8"));
+            Assert.That(_request.Headers["Authorization"], Is.EqualTo("Basic dXNlckBleGFtcGxlLmNvbTpoZXl0aGlzY2FudGJlZ3Vlc3NlZA=="));
+        }
+
+        [Test]
+        public void ThenTheExpectedResultIsReturned()
+        {
+            var optOut = _result.OptOuts.First();
+            Assert.That(optOut.Id, Is.EqualTo(_optOutId));
+            Assert.That(optOut.AccountReference, Is.EqualTo(_accountReference));
+            Assert.That(optOut.ReceivedAt, Is.EqualTo(_receivedAt));
+            Assert.That(optOut.From.PhoneNumber, Is.EqualTo(_phoneNumber));
+
+            Assert.That(_result.PageNumber, Is.EqualTo(1));
+            Assert.That(_result.PageSize, Is.EqualTo(1));
+            Assert.That(_result.TotalItems, Is.EqualTo(1));
+        }
+    }
+}
diff --git a/test/optouts/getall/OptOutsServiceGetAllWithAccountReferenceTests.cs b/test/optouts/getall/OptOutsServiceGetAllWithAccountReferenceTests.cs
new file mode 100644
index 0000000..68cb145
--- /dev/null
+++ b/test/optouts/getall/OptOutsServiceGetAllWithAccountReferenceTests.cs
@@ -0,0 +1,97 @@
+using System;
+using System.Linq;
+using System.Reflection;
+using com.esendex.sdk.optouts;
+using com.esendex.sdk.optouts.models.response;
+using com.esendex.sdk.test.mockapi;
+using Newtonsoft.Json;
+using NUnit.Framework;
+
+namespace com.esendex.sdk.test.optouts.getall
+{
+    [TestFixture]
+    public class OptOutsServiceGetAllWithAccountReferenceTests
+    {
+        private readonly Version _version = Assembly.GetAssembly(typeof(OptOutsService)).GetName().Version;
+        private mockapi.Request _request;
+        private OptOutCollection _result;
+        private string _phoneNumber;
+        private string _accountReference;
+        private int _pageNumber;
+        private int _pageSize;
+        private Guid _optOutId;
+        private DateTime _receivedAt;
+
+        [TestFixtureSetUp]
+        public void Given()
+        {
+            const string username = "user@example.com";
+            const string password = "heythiscantbeguessed";
+
+            _optOutId = Guid.NewGuid();
+            _receivedAt = DateTime.UtcNow;
+            _accountReference = "EX0123456";
+            _phoneNumber = "44123456789";
+
+            var data = new
+            {
+                OptOuts = new[]
+                {
+                    new
+                    {
+                        Id = _optOutId,
+                        ReceivedAt = _receivedAt,
+                        AccountReference = _accountReference,
+                        From = new { PhoneNumber = _phoneNumber }
+                    }
+                },
+                StartIndex = 0,
+                Count = 1,
+                TotalCount = 1
+            };
+
+            _pageNumber = 1;
+            _pageSize = 15;
+
+            MockApi.SetEndpoint(new MockEndpoint(200, JsonConvert.SerializeObject(data), "application/json"));
+
+            var optOutClient = new OptOutsService(MockApi.Url, new EsendexCredentials(username, password));
+
+            _result = optOutClient.GetByAccountReference(_accountReference, _pageNumber, _pageSize);
+            _request = MockApi.LastRequest;
+        }
+
+        [Test]
+        public void ThenTheExpectedRequestIsMade()
+        {
+            var expectedUrl = string.Format("/v1.0/optouts?startIndex={0}&count={1}&accountreference={2}", (_pageNumber - 1) * _pageSize, _pageSize, _accountReference);
+
+            Assert.That(_request.Method, Is.EqualTo("GET"));
+            Assert.That(_request.Url, Is.EqualTo(expectedUrl));
+        }
+
+        [Test]
+        public void ThenTheRequestHasTheExpectedHeaders()
+        {
+            var expectedUserAgent = string.Format("Esendex .NET SDK v{0}.{1}.{2}", _version.Major, _version.Minor, _version.Build);
+            Assert.That(_request.Headers["User-Agent"], Is.EqualTo(expectedUserAgent));
+
+            Assert.That(_request.Headers["Accept"], Is.EqualTo("application/json; charset=utf-8"));
+            Assert.That(_request.Headers["Authorization"], Is.EqualTo("Basic dXNlckBleGFtcGxlLmNvbTpoZXl0aGlzY2FudGJlZ3Vlc3NlZA=="));
+        }
+
+        [Test]
+        public void ThenTheExpectedResultIsReturned()
+        {
+            var optOut = _result.OptOuts.First();
+            Assert.That(optOut.Id, Is.EqualTo(_optOutId));
+            Assert.That(optOut.AccountReference, Is.EqualTo(_accountReference));
+            Assert.That(optOut.ReceivedAt, Is.EqualTo(_receivedAt));
+            Assert.That(optOut.From.PhoneNumber, Is.EqualTo(_phoneNumber));
+
+            Assert.That(_result.PageNumber, Is.EqualTo(1));
+            Assert.That(_result.PageSize, Is.EqualTo(1));
+            Assert.That(_result.TotalItems, Is.EqualTo(1));
+        }
+    }
+}
\ No newline at end of file
diff --git a/test/optouts/getall/OptOutsServiceGetAllWithErrorTests.cs b/test/optouts/getall/OptOutsServiceGetAllWithErrorTests.cs
new file mode 100644
index 0000000..fa1c571
--- /dev/null
+++ b/test/optouts/getall/OptOutsServiceGetAllWithErrorTests.cs
@@ -0,0 +1,50 @@
+using System.Net;
+using com.esendex.sdk.optouts;
+using com.esendex.sdk.test.mockapi;
+using NUnit.Framework;
+
+namespace com.esendex.sdk.test.optouts.getall
+{
+    [TestFixture(403, HttpStatusCode.Forbidden)]
+    [TestFixture(404, HttpStatusCode.NotFound)]
+    [TestFixture(500, HttpStatusCode.InternalServerError)]
+    public class OptOutsServiceGetAllWithErrorTests
+    {
+        private WebException _result;
+        private readonly int _statusCode;
+        private readonly HttpStatusCode _expectedCode;
+
+        public OptOutsServiceGetAllWithErrorTests(int statusCode, HttpStatusCode expectedCode)
+        {
+            _statusCode = statusCode;
+            _expectedCode = expectedCode;
+        }
+
+        [TestFixtureSetUp]
+        public void Given()
+        {
+            const string username = "user@example.com";
+            const string password = "heythiscantbeguessed";
+
+            MockApi.SetEndpoint(new MockEndpoint(_statusCode));
+
+            var optOutClient = new OptOutsService(MockApi.Url, new EsendexCredentials(username, password));
+
+            try
+            {
+                optOutClient.GetAll(1, 2);
+            }
+            catch (WebException ex)
+            {
+                _result = ex;
+            }
+        }
+
+        [Test]
+        public void ThenTheErrorIsReturned()
+        {
+            var webResponse = (HttpWebResponse)_result.Response;
+            Assert.That(webResponse.StatusCode, Is.EqualTo(_expectedCode));
+        }
+    }
+}
\ No newline at end of file
diff --git a/test/optouts/getall/OptOutsServiceGetAllWithFromAndAccountReferenceTests.cs b/test/optouts/getall/OptOutsServiceGetAllWithFromAndAccountReferenceTests.cs
new file mode 100644
index 0000000..154f910
--- /dev/null
+++ b/test/optouts/getall/OptOutsServiceGetAllWithFromAndAccountReferenceTests.cs
@@ -0,0 +1,96 @@
+using System;
+using System.Linq;
+using System.Reflection;
+using com.esendex.sdk.optouts;
+using com.esendex.sdk.optouts.models.response;
+using com.esendex.sdk.test.mockapi;
+using Newtonsoft.Json;
+using NUnit.Framework;
+
+namespace com.esendex.sdk.test.optouts.getall
+{
+    [TestFixture]
+    public class OptOutsServiceGetAllWithFromAndAccountReferenceTests
+    {
+        private readonly Version _version = Assembly.GetAssembly(typeof(OptOutsService)).GetName().Version;
+        private mockapi.Request _request;
+        private OptOutCollection _result;
+        private string _phoneNumber;
+        private string _accountReference;
+        private int _pageNumber;
+        private int _pageSize;
+        private Guid _optOutId;
+        private DateTime _receivedAt;
+
+        [TestFixtureSetUp]
+        public void Given()
+        {
+            const string username = "user@example.com";
+            const string password = "heythiscantbeguessed";
+
+            _optOutId = Guid.NewGuid();
+            _receivedAt = DateTime.UtcNow;
+            _accountReference = "EX0123456";
+            _phoneNumber = "44123456789";
+
+            var data = new 
+            {
+                OptOuts = new[]
+                {
+                    new 
+                    {
+                        Id = _optOutId,
+                        ReceivedAt = _receivedAt,
+                        AccountReference = _accountReference,
+                        From = new { PhoneNumber = _phoneNumber }
+                    }
+                },
+                StartIndex = 0,
+                Count = 1,
+                TotalCount = 1
+            };
+
+            _pageNumber = 1;
+            _pageSize = 15;
+
+            MockApi.SetEndpoint(new MockEndpoint(200, JsonConvert.SerializeObject(data), "application/json"));
+
+            var optOutClient = new OptOutsService(MockApi.Url, new EsendexCredentials(username, password));
+
+            _result = optOutClient.GetByPhoneNumber(_phoneNumber, _accountReference, _pageNumber, _pageSize);
+            _request = MockApi.LastRequest;
+        }
+
+        [Test]
+        public void ThenTheExpectedRequestIsMade()
+        {
+            var expectedUrl = string.Format("/v1.0/optouts?startIndex={0}&count={1}&accountreference={2}&from={3}", (_pageNumber - 1) * _pageSize, _pageSize, _accountReference, _phoneNumber);
+            Assert.That(_request.Method, Is.EqualTo("GET"));
+            Assert.That(_request.Url, Is.EqualTo(expectedUrl));
+        }
+
+        [Test]
+        public void ThenTheRequestHasTheExpectedHeaders()
+        {
+            var expectedUserAgent = string.Format("Esendex .NET SDK v{0}.{1}.{2}", _version.Major, _version.Minor, _version.Build);
+            Assert.That(_request.Headers["User-Agent"], Is.EqualTo(expectedUserAgent));
+
+            Assert.That(_request.Headers["Accept"], Is.EqualTo("application/json; charset=utf-8"));
+            Assert.That(_request.Headers["Authorization"], Is.EqualTo("Basic dXNlckBleGFtcGxlLmNvbTpoZXl0aGlzY2FudGJlZ3Vlc3NlZA=="));
+        }
+
+        [Test]
+        public void ThenTheExpectedResultIsReturned()
+        {
+            var optOut = _result.OptOuts.First();
+            Assert.That(optOut.Id, Is.EqualTo(_optOutId));
+            Assert.That(optOut.AccountReference, Is.EqualTo(_accountReference));
+            Assert.That(optOut.ReceivedAt, Is.EqualTo(_receivedAt));
+            Assert.That(optOut.From.PhoneNumber, Is.EqualTo(_phoneNumber));
+
+            Assert.That(_result.PageNumber, Is.EqualTo(1));
+            Assert.That(_result.PageSize, Is.EqualTo(1));
+            Assert.That(_result.TotalItems, Is.EqualTo(1));
+        }
+    }
+}
\ No newline at end of file
diff --git a/test/optouts/getall/OptOutsServiceGetAllWithFromTests.cs b/test/optouts/getall/OptOutsServiceGetAllWithFromTests.cs
new file mode 100644
index 0000000..96b44d9
--- /dev/null
+++ b/test/optouts/getall/OptOutsServiceGetAllWithFromTests.cs
@@ -0,0 +1,97 @@
+using System;
+using System.Linq;
+using System.Reflection;
+using com.esendex.sdk.optouts;
+using com.esendex.sdk.optouts.models.response;
+using com.esendex.sdk.test.mockapi;
+using Newtonsoft.Json;
+using NUnit.Framework;
+
+namespace com.esendex.sdk.test.optouts.getall
+{
+    [TestFixture]
+    public class OptOutsServiceGetAllWithFromTests
+    {
+        private readonly Version _version = Assembly.GetAssembly(typeof(OptOutsService)).GetName().Version;
+        private mockapi.Request _request;
+        private OptOutCollection _result;
+        private string _phoneNumber;
+        private string _accountReference;
+        private int _pageNumber;
+        private int _pageSize;
+        private Guid _optOutId;
+        private DateTime _receivedAt;
+
+        [TestFixtureSetUp]
+        public void Given()
+        {
+            const string username = "user@example.com";
+            const string password = "heythiscantbeguessed";
+
+            _optOutId = Guid.NewGuid();
+            _receivedAt = DateTime.UtcNow;
+            _accountReference = "EX0123456";
+            _phoneNumber = "44123456789";
+
+            var data = new
+            {
+                OptOuts = new[]
+                {
+                    new
+                    {
+                        Id = _optOutId,
+                        ReceivedAt = _receivedAt,
+                        AccountReference = _accountReference,
+                        From = new { PhoneNumber = _phoneNumber }
+                    }
+                },
+                StartIndex = 0,
+                Count = 1,
+                TotalCount = 1
+            };
+
+            _pageNumber = 1;
+            _pageSize = 15;
+
+            MockApi.SetEndpoint(new MockEndpoint(200, JsonConvert.SerializeObject(data), "application/json"));
+
+            var optOutClient = new OptOutsService(MockApi.Url, new EsendexCredentials(username, password));
+
+            _result = optOutClient.GetByFromAddress(_phoneNumber, _pageNumber, _pageSize);
+            _request = MockApi.LastRequest;
+        }
+
+        [Test]
+        public void ThenTheExpectedRequestIsMade()
+        {
+            var expectedUrl = string.Format("/v1.0/optouts?startIndex={0}&count={1}&from={2}", (_pageNumber - 1) * _pageSize, _pageSize, _phoneNumber);
+
+            Assert.That(_request.Method, Is.EqualTo("GET"));
+            Assert.That(_request.Url, Is.EqualTo(expectedUrl));
+        }
+
+        [Test]
+        public void ThenTheRequestHasTheExpectedHeaders()
+        {
+            var expectedUserAgent = string.Format("Esendex .NET SDK v{0}.{1}.{2}", _version.Major, _version.Minor, _version.Build);
+            Assert.That(_request.Headers["User-Agent"], Is.EqualTo(expectedUserAgent));
+
+            Assert.That(_request.Headers["Accept"], Is.EqualTo("application/json; charset=utf-8"));
+            Assert.That(_request.Headers["Authorization"], Is.EqualTo("Basic dXNlckBleGFtcGxlLmNvbTpoZXl0aGlzY2FudGJlZ3Vlc3NlZA=="));
+        }
+
+        [Test]
+        public void ThenTheExpectedResultIsReturned()
+        {
+            var optOut = _result.OptOuts.First();
+            Assert.That(optOut.Id, Is.EqualTo(_optOutId));
+            Assert.That(optOut.AccountReference, Is.EqualTo(_accountReference));
+            Assert.That(optOut.ReceivedAt, Is.EqualTo(_receivedAt));
+            Assert.That(optOut.From.PhoneNumber, Is.EqualTo(_phoneNumber));
+
+            Assert.That(_result.PageNumber, Is.EqualTo(1));
+            Assert.That(_result.PageSize, Is.EqualTo(1));
+            Assert.That(_result.TotalItems, Is.EqualTo(1));
+        }
+    }
+}
\ No newline at end of file
diff --git a/test/optouts/getall/OptOutsServiceGetAllWithNoResultsTests.cs b/test/optouts/getall/OptOutsServiceGetAllWithNoResultsTests.cs
new file mode 100644
index 0000000..ac574d3
--- /dev/null
+++ b/test/optouts/getall/OptOutsServiceGetAllWithNoResultsTests.cs
@@ -0,0 +1,73 @@
+using System;
+using System.Reflection;
+using com.esendex.sdk.optouts;
+using com.esendex.sdk.optouts.models.response;
+using com.esendex.sdk.test.mockapi;
+using Newtonsoft.Json;
+using NUnit.Framework;
+
+namespace com.esendex.sdk.test.optouts.getall
+{
+    [TestFixture]
+    public class OptOutsServiceGetAllWithNoResultsTests
+    {
+        private readonly Version _version = Assembly.GetAssembly(typeof(OptOutsService)).GetName().Version;
+        private mockapi.Request _request;
+        private OptOutCollection _result;
+        private int _pageSize;
+        private int _pageNumber;
+
+        [TestFixtureSetUp]
+        public void Given()
+        {
+            const string username = "user@example.com";
+            const string password = "heythiscantbeguessed";
+
+            var data = new
+            {
+                StartIndex = 0,
+                Count = 0,
+                TotalCount = 0
+            };
+
+            _pageSize = 15;
+            _pageNumber = 1;
+
+            MockApi.SetEndpoint(new MockEndpoint(200, JsonConvert.SerializeObject(data), "application/json"));
+
+            var optOutClient = new OptOutsService(MockApi.Url, new EsendexCredentials(username, password));
+
+            _result = optOutClient.GetAll(_pageNumber, _pageSize);
+            _request = MockApi.LastRequest;
+        }
+
+        [Test]
+        public void ThenTheExpectedRequestIsMade()
+        {
+            var expectedUrl = string.Format("/v1.0/optouts?startIndex={0}&count={1}", (_pageNumber - 1) * _pageSize, _pageSize);
+
+            Assert.That(_request.Method, Is.EqualTo("GET"));
+            Assert.That(_request.Url, Is.EqualTo(expectedUrl));
+        }
+
+        [Test]
+        public void ThenTheRequestHasTheExpectedHeaders()
+        {
+            var expectedUserAgent = string.Format("Esendex .NET SDK v{0}.{1}.{2}", _version.Major, _version.Minor, _version.Build);
+
+            Assert.That(_request.Headers["Accept"], Is.EqualTo("application/json; charset=utf-8"));
+            Assert.That(_request.Headers["Authorization"], Is.EqualTo("Basic dXNlckBleGFtcGxlLmNvbTpoZXl0aGlzY2FudGJlZ3Vlc3NlZA=="));
+            Assert.That(_request.Headers["User-Agent"], Is.EqualTo(expectedUserAgent));
+        }
+
+        [Test]
+        public void ThenTheExpectedResultIsReturned()
+        {
+            Assert.That(_result.PageNumber, Is.EqualTo(1));
+            Assert.That(_result.PageSize, Is.EqualTo(0));
+            Assert.That(_result.TotalItems, Is.EqualTo(0));
+
+            Assert.That(_result.OptOuts.Count, Is.EqualTo(0));
+        }
+    }
+}
\ No newline at end of file
diff --git a/test/optouts/getbyid/OptOutsServiceGetByIdTests.cs b/test/optouts/getbyid/OptOutsServiceGetByIdTests.cs
new file mode 100644
index 0000000..7e1867b
--- /dev/null
+++ b/test/optouts/getbyid/OptOutsServiceGetByIdTests.cs
@@ -0,0 +1,78 @@
+using System;
+using System.Reflection;
+using com.esendex.sdk.optouts;
+using com.esendex.sdk.optouts.models.response;
+using com.esendex.sdk.test.mockapi;
+using Newtonsoft.Json;
+using NUnit.Framework;
+
+namespace com.esendex.sdk.test.optouts.getbyid
+{
+    [TestFixture]
+    public class OptOutsServiceGetByIdTests
+    {
+        private readonly Version _version = Assembly.GetAssembly(typeof(OptOutsService)).GetName().Version;
+        private mockapi.Request _request;
+        private OptOut _result;
+        private string _phoneNumber;
+        private string _accountReference;
+        private DateTime _receivedAt;
+        private Guid _optOutId;
+
+        [TestFixtureSetUp]
+        public void Given()
+        {
+            const string username = "user@example.com";
+            const string password = "heythiscantbeguessed";
+
+            _optOutId = Guid.NewGuid();
+            _receivedAt = DateTime.UtcNow;
+            _accountReference = "EX0123456";
+            _phoneNumber = "44123456789";
+
+            var data = new
+            {
+                Id = _optOutId,
+                ReceivedAt = _receivedAt,
+                AccountReference = _accountReference,
+                From = new
+                {
+                    PhoneNumber = _phoneNumber
+                }
+            };
+
+            MockApi.SetEndpoint(new MockEndpoint(200, JsonConvert.SerializeObject(data), "application/json"));
+
+            var optOutClient = new OptOutsService(MockApi.Url, new EsendexCredentials(username, password));
+
+            _result = optOutClient.GetById(_optOutId);
+            _request = MockApi.LastRequest;
+        }
+
+        [Test]
+        public void ThenTheExpectedRequestIsMade()
+        {
+            Assert.That(_request.Method, Is.EqualTo("GET"));
+            Assert.That(_request.Url, Is.EqualTo(string.Format("/v1.0/optouts/{0}", _optOutId)));
+        }
+
+        [Test]
+        public void ThenTheRequestHasTheExpectedHeaders()
+        {
+            var expectedUrl = string.Format("Esendex .NET SDK v{0}.{1}.{2}", _version.Major, _version.Minor, _version.Build);
+
+            Assert.That(_request.Headers["Accept"], Is.EqualTo("application/json; charset=utf-8"));
+            Assert.That(_request.Headers["Authorization"], Is.EqualTo("Basic dXNlckBleGFtcGxlLmNvbTpoZXl0aGlzY2FudGJlZ3Vlc3NlZA=="));
+            Assert.That(_request.Headers["User-Agent"], Is.EqualTo(expectedUrl));
+        }
+
+        [Test]
+        public void ThenTheExpectedResultIsReturned()
+        {
+            Assert.That(_result.Id, Is.EqualTo(_optOutId));
+            Assert.That(_result.ReceivedAt, Is.EqualTo(_receivedAt));
+            Assert.That(_result.AccountReference, Is.EqualTo(_accountReference));
+            Assert.That(_result.From.PhoneNumber, Is.EqualTo(_phoneNumber));
+        }
+    }
+}
diff --git a/test/optouts/getbyid/OptOutsServiceGetByIdWithErrorResponseTests.cs b/test/optouts/getbyid/OptOutsServiceGetByIdWithErrorResponseTests.cs
new file mode 100644
index 0000000..abbcc38
--- /dev/null
+++ b/test/optouts/getbyid/OptOutsServiceGetByIdWithErrorResponseTests.cs
@@ -0,0 +1,52 @@
+using System;
+using System.Net;
+using com.esendex.sdk.optouts;
+using com.esendex.sdk.test.mockapi;
+using NUnit.Framework;
+
+namespace com.esendex.sdk.test.optouts.getbyid
+{
+    [TestFixture(403, HttpStatusCode.Forbidden)]
+    [TestFixture(404, HttpStatusCode.NotFound)]
+    [TestFixture(500, HttpStatusCode.InternalServerError)]
+    public class OptOutsServiceGetByIdWithErrorResponseTests
+    {
+        private readonly int _statusCode;
+        private readonly HttpStatusCode _expectedCode;
+        private WebException _result;
+
+        public OptOutsServiceGetByIdWithErrorResponseTests(int statusCode, HttpStatusCode expectedCode)
+        {
+            _statusCode = statusCode;
+            _expectedCode = expectedCode;
+        }
+
+        [TestFixtureSetUp]
+        public void Given()
+        {
+            const string username = "user@example.com";
+            const string password = "heythiscantbeguessed";
+            var optOutId = Guid.NewGuid();
+
+            MockApi.SetEndpoint(new MockEndpoint(_statusCode));
+
+            var optOutClient = new OptOutsService(MockApi.Url, new EsendexCredentials(username, password));
+
+            try
+            {
+                optOutClient.GetById(optOutId);
+            }
+            catch (WebException ex)
+            {
+                _result = ex;
+            }
+        }
+
+        [Test]
+        public void ThenTheErrorIsReturned()
+        {
+            var webResponse = (HttpWebResponse)_result.Response;
+            Assert.That(webResponse.StatusCode, Is.EqualTo(_expectedCode));
+        }
+    }
+}
\ No newline at end of file
diff --git a/test/surveys/SurveysServiceTests.cs b/test/surveys/SurveysServiceTests.cs
index f5dad75..8ba2885 100644
--- a/test/surveys/SurveysServiceTests.cs
+++ b/test/surveys/SurveysServiceTests.cs
@@ -3,7 +3,7 @@
 using System.Reflection;
 using com.esendex.sdk.surveys;
 using com.esendex.sdk.test.mockapi;
-using com.esendex.sdk.test.models.requests;
+using com.esendex.sdk.test.models.requests.surveys;
 using Newtonsoft.Json;
 using NUnit.Framework;
 
@@ -16,6 +16,8 @@ public class SurveysServiceTests
         private Guid _surveyId;
         private string _recipient;
         private mockapi.Request _request;
+        private string _expectedUrl;
+        private string _expectedUserAgent;
 
         [TestFixtureSetUp]
         public void Given()
@@ -25,7 +27,10 @@ public void Given()
             _recipient = "44123456789";
             _surveyId = Guid.NewGuid();
 
-            MockApi.SetEndpoint(new MockEndpoint(200, "", "text/plain"));
+            _expectedUrl = string.Format("/v1.0/surveys/{0}/send", _surveyId);
+            _expectedUserAgent = string.Format("Esendex .NET SDK v{0}.{1}.{2}", _version.Major, _version.Minor, _version.Build);
+
+            MockApi.SetEndpoint(new MockEndpoint(200, contentType: "text/plain"));
 
             var surveysClient = new SurveysService(MockApi.Url, new EsendexCredentials(username, password));
 
@@ -37,7 +42,7 @@ public void Given()
         public void ThenTheExpectedRequestIsMade()
         {
             Assert.That(_request.Method, Is.EqualTo("POST"));
-            Assert.That(_request.Url, Is.EqualTo(string.Format("/v1.0/surveys/{0}/send", _surveyId)));
+            Assert.That(_request.Url, Is.EqualTo(_expectedUrl));
         }
 
         [Test]
@@ -57,7 +62,7 @@ public void ThenTheRequestHasTheExpectedHeaders()
             Assert.That(_request.Headers["Accept"], Is.EqualTo("application/json; charset=utf-8"));
             Assert.That(_request.Headers["Authorization"], Is.EqualTo("Basic dXNlckBleGFtcGxlLmNvbTpoZXl0aGlzY2FudGJlZ3Vlc3NlZA=="));
             Assert.That(_request.Headers["Content-Type"], Is.EqualTo("application/json; charset=utf-8"));
-            Assert.That(_request.Headers["User-Agent"], Is.EqualTo(string.Format("Esendex .NET SDK v{0}.{1}.{2}", _version.Major, _version.Minor, _version.Build)));
+            Assert.That(_request.Headers["User-Agent"], Is.EqualTo(_expectedUserAgent));
         }
     }
 }
diff --git a/test/surveys/SurveysServiceWithBadRequestTests.cs b/test/surveys/SurveysServiceWithBadRequestTests.cs
index e7a88fc..fc0a2e4 100644
--- a/test/surveys/SurveysServiceWithBadRequestTests.cs
+++ b/test/surveys/SurveysServiceWithBadRequestTests.cs
@@ -1,7 +1,6 @@
 using System;
-using System.Net;
-using com.esendex.sdk.exceptions;
 using com.esendex.sdk.surveys;
+using com.esendex.sdk.surveys.models;
 using com.esendex.sdk.test.mockapi;
 using Newtonsoft.Json;
 using NUnit.Framework;
@@ -11,7 +10,7 @@ namespace com.esendex.sdk.test.surveys
     [TestFixture]
     public class SurveysServiceWithBadRequestTests
     {
-        private WebException _result;
+        private SurveyResult _result;
         private string _errorValue;
         private string _errorDescription;
         private string _errorCode;
@@ -44,32 +43,16 @@ public void Given()
 
             var surveysClient = new SurveysService(MockApi.Url, new EsendexCredentials(username, password));
 
-            try
-            {
-                surveysClient.Send(surveyId, recipient);
-            }
-            catch (WebException ex)
-            {
-                _result = ex;
-            }
+            _result = surveysClient.Send(surveyId, recipient);
         }
 
         [Test]
-        public void ThenTheErrorIsReturned()
+        public void ThenTheResultContainsTheErrors()
         {
-            var webResponse = (HttpWebResponse)_result.Response;
-            Assert.That(webResponse.StatusCode, Is.EqualTo(HttpStatusCode.BadRequest));
-        }
-
-        [Test]
-        public void ThenTheExceptionContainsTheErrors()
-        {
-            var badRequest = (BadRequestException) _result;
-
-            Assert.That(badRequest.Errors[0].Code, Is.EqualTo(_errorCode));
-            Assert.That(badRequest.Errors[0].Description, Is.EqualTo(_errorDescription));
-            Assert.That(badRequest.Errors[0].Values[0], Is.EqualTo(_errorValue));
-            Assert.That(badRequest.Errors[0].Values[1], Is.EqualTo(_errorValue2));
+            Assert.That(_result.Errors[0].Code, Is.EqualTo(_errorCode));
+            Assert.That(_result.Errors[0].Description, Is.EqualTo(_errorDescription));
+            Assert.That(_result.Errors[0].Values[0], Is.EqualTo(_errorValue));
+            Assert.That(_result.Errors[0].Values[1], Is.EqualTo(_errorValue2));
         }
     }
 }
\ No newline at end of file
diff --git a/test/surveys/SurveysServiceWithTemplateFieldsTests.cs b/test/surveys/SurveysServiceWithTemplateFieldsTests.cs
index d63c13d..9f182f1 100644
--- a/test/surveys/SurveysServiceWithTemplateFieldsTests.cs
+++ b/test/surveys/SurveysServiceWithTemplateFieldsTests.cs
@@ -4,7 +4,7 @@
 using System.Reflection;
 using com.esendex.sdk.surveys;
 using com.esendex.sdk.test.mockapi;
-using com.esendex.sdk.test.models.requests;
+using com.esendex.sdk.test.models.requests.surveys;
 using Newtonsoft.Json;
 using NUnit.Framework;
 
@@ -18,6 +18,8 @@ public class SurveysServiceWithTemplateFieldsTests
         private string _recipient;
         private Dictionary<string, string> _templateFields;
         private mockapi.Request _request;
+        private string _expectedUrl;
+        private string _expectedUserAgent;
 
         [TestFixtureSetUp]
         public void Given()
@@ -27,7 +29,10 @@ public void Given()
             _recipient = "44123456789";
             _surveyId = Guid.NewGuid();
 
-            MockApi.SetEndpoint(new MockEndpoint(200, "", "text/plain"));
+            _expectedUrl = string.Format("/v1.0/surveys/{0}/send", _surveyId);
+            _expectedUserAgent = string.Format("Esendex .NET SDK v{0}.{1}.{2}", _version.Major, _version.Minor, _version.Build);
+
+            MockApi.SetEndpoint(new MockEndpoint(200, contentType: "text/plain"));
 
             var surveysClient = new SurveysService(MockApi.Url, new EsendexCredentials(username, password));
             _templateFields = new Dictionary<string, string> { {"Field", "Value"}};
@@ -40,7 +45,7 @@ public void Given()
         public void ThenTheExpectedRequestIsMade()
         {
             Assert.That(_request.Method, Is.EqualTo("POST"));
-            Assert.That(_request.Url, Is.EqualTo(string.Format("/v1.0/surveys/{0}/send", _surveyId)));
+            Assert.That(_request.Url, Is.EqualTo(_expectedUrl));
         }
 
         [Test]
@@ -60,7 +65,7 @@ public void ThenTheRequestHasTheExpectedHeaders()
             Assert.That(_request.Headers["Accept"], Is.EqualTo("application/json; charset=utf-8"));
             Assert.That(_request.Headers["Authorization"], Is.EqualTo("Basic dXNlckBleGFtcGxlLmNvbTpoZXl0aGlzY2FudGJlZ3Vlc3NlZA=="));
             Assert.That(_request.Headers["Content-Type"], Is.EqualTo("application/json; charset=utf-8"));
-            Assert.That(_request.Headers["User-Agent"], Is.EqualTo(string.Format("Esendex .NET SDK v{0}.{1}.{2}", _version.Major, _version.Minor, _version.Build)));
+            Assert.That(_request.Headers["User-Agent"], Is.EqualTo(_expectedUserAgent));
         }
     }
 }
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