Overcharged again

They certainly can give you credit for the over charge. The trick is finding an agent that will do it. 

Prepaid cannot overcharge.   If you are missing an autopay credit because you had to pay manually, it's not overcharge.

Prepaid auto pay is taken from your method of payment up to 48 hours before refill date, which is midnight on your renewal date.   

If your method of payment doesn't have funds, or payment fails, att doesn't resubmit, and may not allow that payment method again. 

I suggest PayPal, which can have multiple ways of funding, or AT&T refill cards. 

[EDITED] AT&T told me it was a glitch in their system that caused the autopay to not process.   They did give me an autopay credit but not as much as it was supposed to be.    That means that they Mist definitely DID overcharge me.   Not sure where you get the idea that they cannot overcharge? [EDITED]  I am switching away fromAT&T because of this.    The rep told me that the issue happened to everyone who received the old “grandfathered” credits and they can’t correct the issue they created.   

[EDITED per Community Guidelines]

@MopTopLisa keep your responses civil and polite this is a customer populated forum with no access to your account or see why or how you are overcharged as you say, they are people that donate their own time to try and assist other customers.

That was civil and polite.   Thanks for adding nothing to the solution 

Your an AT&T employee?  Why not add to the solution instead of just adding drama.  

constructive is a pole engineer not a wireless employee. He is required to have the employee tag because he does work for AT&T.