ADT Pathetic Service Delivery

I am tired of ADT that constantly calls me for outstanding balance that I do not owe. They have handed me over to attorneys due to not cancelling my contract I have spoken to a lady that have contacted me wrt the account. We moved into this house in July 2020. We had the alarm system for 2 months and thereafter cancelled the service in beginning September. I still had to pay end September which I did.

Mid September 2020 ADT came and removed their equipment. So how was this service never cancelled as I’ve paid my last instalment in September and equipment was removed

Please communicate with ADT or ask someone to call me urgently as this is affecting ring my credit profile due to someone clearly not doing their job

Kind regards

Mrs A. Buntting ***