Inappropriate billing practices

I canceled my AT&T accounts a year ago and transferred all of my family’s devices to another carrier. However, AT&T continued to charge me monthly with respect one device ($112/mo). I never used this device with AT&T over that period and I never received any bill. I eventually saw the recurring charge on my credit card statement. I called customer service to request a refund and prevent the charge going forward. I was transferred to various employees over the course of an hour and was told I would receive a partial refund. I said that was a good start and I accepted it but I also said that I was owed a full refund. At this point, the employee rudely yelled at me, changed his mind about the partial refund and hung up on me. I was unhappy but never rude or disrespectful. I called back immediately and had a more professional representative who promised to submit the case for review and indicated I would receive an email with AT&T’s decision. I found this was unfair but had no choice. I never did receive any email. I have never been reimbursed any of my nearly $1000 and, I just received a BILL from AT&T, where I have no service at all, for $118 which you sent to a collection service with a highly dubious business reputation. This is totally unprofessional conduct, and much worse. I was a customer for many years and paid every bill on time. I was respectful and asked that the error be addressed. Everyone acknowledged it was an error. Please rectify this immediately.