What is the correct email address to get my payment posted?!?!?!?!?!?

I paid my bill and it was credited to the wrong account. I FINALLY (after a grand total of over FOUR hours on hold over the course of 2 days just trying to get a human on the phone) spoke to someone today who told me to email my proof of payment to attpaymentclaims@att.net. I asked her to clarify and spell it three times to make sure I had it right. I sent the email, and it bounced back saying the email address was invalid. I have now tried 3 other variations on the email address trying to get it to go through, and they have all bounced back. This is beyond ridiculous now! WHAT IS THE CORRECT EMAIL ADDRESS?!?!?!?!?!?!? Alternatively, what's the fax number? My bank tried to get that, and every time they called to get it, they got disconnected.