Cannot log into my att.com account

I am a internet customer and as of last week, I am unable to log into my att.com account. It all started when I ordered wireless service to be added to my account. I have called in 4 times to resolve this issue and attempted all recommended fixes including using 3 different browsers; Chrome, Firefox, IE. I also cleared cache in all of them. I am not able to pay my bill. Please advise.

. I need to be able to access the account to pay my bill. How do I resolve this issue?