Harassment and inconvenience

I have been a loyal customer for years. Added some features to my plan and the manager I dealt with was inappropriate in many ways!!! I called this in to at&t and the person I spoke with said my account would be credited for the entire month of April-May. I insisted that they did not need to do that but, the person I was speaking with insisted it be done. Then, I get a bill in the mail the other day that states it was never taken off of my account so, I called back and they yet again insisted that it would be. Still, it's on my bill and now it states that being its a past due balance....it HAS to be paid today for no shut off! I cannot believe this and I want it taken care of immediately please.