Here is the situation. Trying to leave T-Mobile due to some billing issues that I won't go into since I don't want to bash T-Mobile on a public forum. We have multiple iPhones that are paid in full. We received SIM cards from another provider only to find out that T-Moblie has blacklisted the IMEIs on those phones.
How do we go about getting these phones off the blacklist?
Best answer by smplyunprdctble
Blacklist, or are they SIM-locked?
Blacklist means you didn't pay for the phone (possibly that you owe them other monies, not 100% certain on this one), so they are able to do what they want to make it painful. You suggest you paid for the phones in full, so I'll believe this is not the case.
All phones from T-Mobile are SIM-locked to T-Mobile (same with any carrier). iPhones are SIM-locked to the first carrier they are connected to. You need to contact the carrier to get your device SIM-unlocked: Unlock your mobile wireless device . You have to meet all the required items in the document, and you can contact T-Mobile to get an unlock code.