Double billed - DirecTV

I have had nothing but problems with ATT billing over the past 60 days. My account was double billed in September 2016. Refund was issued, but added to my October 2016 bill.I have disputed the charge with my credit card company. November bill now reflects a doubling of my October bill. I am being overcharged by over $400.00. I have spent 5-1/2 hours on the phone with 5 different ATT representatives. I have been hung up on once, and placed on hold for over 45 minutes by another. A formal complaint was filed with ATT on 10/31/2016 (without a single response)

This question, "Double billed," is about DirecTV channels, programming, equipment, and sports.