How to unlock an iPhone to use with a different carrier?
Mother-in-law bought 7 Pro on eBay. She’s on our family plan and her AT&T SIM card worked for several years. She upgraded the phone and now wants to use the 7 Pro on a service like Mint mobile or Consumer cellular. Unlock request denied because the phone is still registered to another account. Have no idea whose account. How can I find out or get around that to get the unlock.
[Re-Titled by Moderator]
Earlier iPhone models