Double billed for AT&T Direct TV since March 2018 - How to recoop $3463.93

I've reached out to AT&T loyalty twice now. My husband has lung cancer and I've taken over reviewing our credit card bills. Imagine my surprise when I noticed years and years of AT&T Direct TV billing us 2x every month. The first time I contacted their loyalty group they found 2 accounts and noted one had been cancelled in 2018 but was still being billed. The rep even calculated the amount she would escalate to be refunded $3463.93 and said I would receive an email or phone call confirming how they would credit this amount within 7 business days. Today, I contacted them and the first person I spoke with saw that reps notes. However, when I was transferred today, the loyalty rep couldn't find any notes or any indication of the double billing....what? And, I had the ID for the rep I had previously spoken with but was told it wasn't in their power to contact her....Sounds like AT&T right. 

Somehow they must have lost the records when they recently credited - according to them - $92 for 4 months to my credit card. My plan is to report this fraud to my credit card company, to the Better Business Bureau and to the FTC unless AT&T adequately addresses this now.  Please beware when you allow AT&T to bill your credit card. Their systems are pretty messed up and/or they are trying to cheat their customers.