Switched from T-Mobile screwed out of 2 phones

So we were talked into changing providers from T-Mobile to AT&T with the promise that they would pay UP to $650 for the 2 phones we already had . The people who work at the Shrewsbury att store have to be the SLOWEST people ever hired . It took OVER 3 hrs for this process . After we returned from a trip we went down to turn in the paperwork saying we paid for our phones because that’s T-Mobile’s deal and that’s when we were told it’s the wrong paperwork . Mind you that’s what they asked for so after running around and double checking we go back with more paperwork waited another 1.5 hrs with only one customer in the building we were told we would have to call the main office . After that 1 hr phone call we still get the run around and 3 months later we still have not received our money back or the 2 phones we paid for back. This company has to be the worst to deal with and after reading all the reviews on 5 stores I see I’m not alone . Has this happened to anyone else and how did you get your money back ????