well i purchased the x5c and have been using it on t-mobile now for a day, so far so good, no issues what so ever. some overheating but not to the point that my phone is slowing down or any glitches. my 1 concern is, how can i turn on wifi calling with this phone. my sister has t-mobile with iphone and you can turn it on via wifi, but not sure how you do it with the x5c. if any 1 can help. thanks!