Urgent message - Bill payment error

Tuesday evening suddenly my U-verse service suddenly showed me a blue screen reading URGENT MESSAGE:  To pay your AT&T bill today, go to att.com/myatt, use the myAT&T mobile app on your smartphone, or call 800.288.2020 and say "pay my bill" when prompted.  

This is on all channels except a few most local ones, and in the Guide every channel thus effected has been replaced by BILL and every program listed as AT&T Bill Pay Notification.

Multiple calls to Billing/Accounting confirm that my balance is at 0, and there was no missed payment.  Multiple technicians assured me that the issue would be fixed "later tonight" or "by tomorrow morning", to no avail, as it is now Thursday evening.  Have tried rebooting/repowering modem, U-Verse box, etc.  This error appeared suddenly on its own, and there is no late payment or outstanding balance.  How is this not a familiar problem with a simple solution?  Technicians have been unhelpful and have seem mystified, and there's no reason why locating the error once the balance is confirmed and making the adjustment should take hours.  

Thanks