Why should tmobile care what phone I use on their services. Tmobile is a service provider and I paid for service that I can no longer use. Tmobile never has and from my knowledge never will begin to manufacture phones. So they should continue to be just that, a service provider. It’s interesting that when I call they always ask what phone are you using, when they already know.

Update:
It appears that when you remove the data settings from the iPhone and reenter them without guest as username and password it works again. Strange very strange.