The unlock request was submitted on 4/15/14 and was approved on 4/16/14. I did the restore and all the stuff they say to do. I then put my tmobile sim and it says sim invalid. I called Apple and they said they have not received the unlock request from AT&T. I am not an AT&T customer so I had the sel

Hello, I have AT&T phone unlocked network. I want to factory reset this device. But i worrying about device going back to locked again. If im factory reset this device, does it still remain unlocked the network? Thanks