AT&T U-verse Service

I had an AT&T U-verse TV and Internet package.  I cancelled my AT&T U-verse TV in August of 2022 and switched to Direct TV Stream.  I retained my Internet Service.  Why am I being billed each month after the cancellation for AT&T U-verse ? ( September, October, November) My account was current and the final AT&T U- verse obligation has been fulfilled.  I called Customer Service on numerous occasions.  Each time I called I was informed that the error has been corrected.  Every subsequent month I still see an AT&T U-verse charge in addition to a message stating my bill is past due.  Why  is this continually occurring?