ATT Account cancelled, don't know why

An elderly family member with U-300 U-verse, internet, and phone bundle for many years has had her account cancelled twice in July. First time was for a problem with auto-pay failing for several months. Got that resolved by paying over $1,000. A technician was sent out to "inspect" the equipment, nothing was replaced, and all services were restored. It was again cancelled July 26 and no one in CS can tell us why. We have a credit balance where ATT will send us a check. CS enabled services except U-verse TV only has basic channels. There seems to be some disagreement between CS Billing and CS Technical. Technical says our equipment is good to go, but Billing seems to be holding up the account waiting for Technical. How do we get this resolved? We've spent hours over many days phoning and chatting with CS and nothing gets resolved.

By the way, we've given up on auto-pay for now and will pay manually every month. Part of the problem was difficulty accessing the account and not getting mail/emails to know the account was in trouble. I manage most of my accounts by auto-pay and have never had any problems. We've seen other people who have had issues. Accounts being paid by CC for years by auto-pay suddenly stop getting accepted, etc. It can happen for no reason.