I have a Nokia 920 that was on AT&T and now it's unlocked. I've been able to set it up on TMobile (south Florida area in case location matters) however, I'm having issues with getting and sending mms as well as slow internet. I've updated the settings a few times and it'll start working but then stop again. I've spent hours on the phone with tMobile and they haven't been able to help. Does anyone have any suggestions?