ATT Next Up phone return issues!

I’ve been given the run around this year trying to return my ATT next up phone. I’ve spent over 5 hours between calls and have gotten nowhere. I upgrade my phone at the Apple Store via Next Up and need to send the old phone back but no one can help me. Can’t get a shipping label, Apple says I may get a return label at some point but doesn’t see a trade in on the order and the ATT store won’t take the phone back. I’m honestly just ready to move to a different provider at the is point because of how useless this program has been. I had a lost return in the past and the Office of the President helped me before but I just want to do something as simple as return this phone with a shipping label.

Can anyone help?