Wrong Service provider displayed, unable to change

[MadameMalady]

Hardware- Pinephone Pro Developer Edition
Software- Mobian, and the latest 7.4 modem firmware from here.

I have a Mint mobile sim, that worked great on previous versions of the firmware, now it displays as either 'cellular' or 'T-mobile', and no longer accepts or can make calls (it can text) (I think the mis-labeling of the provider and lack of calling are probably the same issue).
I can't change the provider, it gets switched right back.

The sim has been swapped around to different phones, and this happened after using it with an iphone for a bit, I don't know a lot abt modems or sim cards, but could the iphone have written a bit of data that the modem firmware doesnt know how to read?

If you'd like me to run any commands and provide debug logs, just tell me what!