I have a factory unlocked iPhone 4 that I just upgraded to ios 7. I have often had struggles with iMessages being on T-Mobile and not having a data plan. The problem I am having is that my phone number seems to keep deactivating from imessages and so then imessages reverts to my email. This is particularly frustrating because then messages are sent only to my commuter and not my phone. I have done different things to get the number to reactivate and it works but then after some time it deactivates again. Any thoughts?