bought an AT&T iphone 7 on letgo. I'm a sucker as the guy told me he would get the unlock code for the the next day. of course, he blocked me. Turns out it is blacklisted for whatever reason. I need to use it on tmobile. I've tried unlocking services which say that AT&T won't give them the unlock code. any suggestions?
but once it was jailbroken, you could then install a script that would unlock it and set-up the network info to work with t-mobile. i have not had a reason to do this in years but it was very easy to do the last time i did it. pretty sure it was an iphone 5(s?) that i last did this to. figured it would be worth looking into in case it is still possible to do.