Billing Complaint

I paid my U-verse with autopay. I paid the full bill on 8/13/2017 through my checking account. I wanted to switch the payment method to my credit card and no one said that it would change my payment due date or cause me to be billed twice, but I was again billed on 8/31/2017. I was told that my next payment due date would be 9/30/2017. I wasn't notified because AT&T sent out the notices before I changed my payment method to credit card. How does this not have me overpaying? In the month of August 2017, AT&T was paid about $517 using autopay and I made this change just 2 weeks ago. I am a long time AT&T customer! I am not a new customer and it seems to me that this is fraud, plain and simple! I was told to call the AT&T corporate office, but aren't they the same goniffs that put this ripoff into place? How does AT&T justify taking over $515 from me in one month and not call it 'theft'? Any thoughts on this? I am going to contact the Florida Attorney General's office to file a complaint and see how AT&T is getting away with this without notifying its' customers
of years and years! How can this be legal and what are people doing to stop AT&T from robbing its' customers blind? Someone at AT&T is getting rich with these extra payments and then telling its customers that they aren't paying more than than have in the past and in my case for more than the last two years! I think I know the difference between my normal bill of $253 and my two August 2017 bills which come to about $517! I want someone at AT&T to stand up and be accountable to its' customers and honestly explain what is going on and why is no one else demanding that AT&T explain this blatant theft of our money? How many customers have to be ripped off before this despicable theft of customers' monies are exposed and AT&T has to answer for it? Theft is theft and AT&T doesn't get to sweep this under the rug and not offer its customers a proper explanation for why AT&T thinks it's entitled to take even more of our monies without any notice or explanation and also be entitled to keep doing it without giving a thought to its' customers who are being purposely duped into paying an extra payment and then being connected to customer service who have no idea of why this is happening, but offer explanations that insult our intelligence when they make no sense whatsoever! Anyone have anything to offer about how this continues to happen with AT&T getting even richer by the day on the backs of their customers who are 'being taken for a ride' and once again, no one at AT&T has to 'pay the piper' by being investigated and then charged for being, at the very least, complicit in screwing its' customers royally with bogus charges that even customer service can't understand nor explain away when its' customers want to know 'where's my money?'

[Title edited to reflect new topic.]