my sister purchased a galaxy s21 from sprint before the tmobile merger. she finished paying it off after the merger and upgraded to an iphone. After paying the phone off she gifted the phone to my mother who at the time was with tmobile so she simply popped in her sim card and the phone worked great. now she has made the switch to att and tmobile states the phone is unlocked yet the phone is uicc locked. we get a sim card not provisioned error with att sim card. what if anything can be done to get this phone uicc unlocked?
Happened to me on a paid iPhone 6S years ago and even after pay off it took multiple attempts till they got it right.
I haven't been able to get my Note 8 or S21+ unlocked through T-Mobile. Almost 10 hours of phone calls and still have locked phones. Samsung has been no help either. Neither one want any future business from me.