Cannot sign into myatt online or on phone app. Customer service wasn't able to help.

Tried to sign into myatt first on my phone, then using my computer. I keep getting a message that the ID and password are not in ATT's records. I tried to use the password recovery feature but got the same error message. I called customer support. They looked up my account then tried to walk me through changing the password. Still got the same error message. Customer support then had me go to ufix.att.com to set up a new password. I was able to set up a new password and successfully log in and out of ufix.att.com. But when I tried to look at my bill, even though I was already logged in at ufix.att.com, I was routed to this webpage where you sign into myatt. When I tried to sign in using the new password, I got the same error message about the ID and password not matching and/or not in ATT's records. The end result: I can sign into ufix.att.com successfully, but cannot sign into myatt. Does anyone have any suggestions?