ATT charged me 3 times and denies it

There is something wrong with your payment system. I tried to pay my bill with a credit card and it got declined although there is nothing wrong with the card. So I put in my checking and it went through. Turns out you charged me 3 times, and the original card went through 2ce. When I called ATT they denied it, even though I am sitting here looking at bank transactions at Wells Fargo online and also called the Bank to confirm it. You have the credit card information and you should be able to refund the money. They said I have to fax in proof with a Bank Statement. My bank is going to dispute it but of course, this all takes time and in the meantime, ATT is using my money. Cheating and lying