POOR BILLING SYSTEM AT ADT

I was using ADT security in my house up until this year January 2018, where i decided to use other security company due to poor service and inconsiderate of the company, but still i am still having that problem ,they are debiting monthly installment mean while i am no longer with them, and when i ask why they are doing that no body take responsibility, instead i was told to send an email , they will respond with the way forward as the ABSA account they using i am no longer using it due to them, and now i am carrying reverse charges that they do not want to take charge of them