I also had issues with AT&T that i finally got rid of them last year. There customer service sucks because everything gets routed to a call center in India and they do not fully understand or maybe not have the technology to check past records. I ended up filing a complaint with (I believe) the FCC and that got me a call within a few days from someone based in LA that could see and understand my billing issues. It even took that rep almost a month to rectify but she did follow up weekly with an update.
In the end, I was just done with ATT as took too much of my time to rectify what should have been a 15 minute phone call. I switched to Youtube TV and love it. It is about $20 cheaper than my ATT bill and I get more of the channels I actually wanted.