Billing Department

After two years of internet issues - slow speeds and dropped signals - I finally decided to upgrade (so I'm told) to U-verse.  Once I upgraded it seems that my bill was no longer a combined bill.  No one ever told me that all my account numbers would be changing so on the first bill I received I paid it like normal.  This was evidently just my wireless bill.  That payment has been lost in ATT accounting for a month and a half at this point.  I have called in twice and was told twice that the situation was taken care of.  I called today - because I still have larege red type on my account - and was told that nothing had been done about it and that it would now take until the 28th of January to resolve the issue.  The catch is my son's phone is not working and we were looking at upgrading it.  I can't do that until I get the "past due" notice off my bill.    All I get from the ATT reps I talk to is  - I'm sorry we can't do anything to speed up the process.   I actually have a phone number to the Office of the President because of all the issues we had with our internet service.  I'm really thinking about using that number to call and complain.  Anyone have any other suggestions?