diff --git a/src/Express100.php b/src/Express100.php
index 798fafe..59d17c1 100644
--- a/src/Express100.php
+++ b/src/Express100.php
@@ -76,8 +76,8 @@ public function track($tracking_code = '', $shipping_code = '', $phone = '')
             'num' => $tracking_code,
         ];
 
-        if (!empty($mobile)) {
-            $data['mobiletelephone'] = $phone;
+        if (!empty($phone)) {
+            $data['phone'] = $phone;
         }
 
         $post['param'] = json_encode($data);