Car track bad service

I sold my car last year around April and I called car track to inform them because the new owner wanted to take over the car track account and I was assured that it could be done.everything was done only for car track to continue running their debit order on my account..I started receiving emails from cartrack stating that I owe them and I sent an email back explaining the entire issue. 2 months ago I got an SMS again and I called in and asked them to go back to the telephonic conversation I had with the consultant and fix this issue but a few days ago they have attempted to take money from my account again..Nobody has attempted to resolve my issue despite emails,phone calls that I made and all I get is people running debit orders on my account whenever they feel like doing so...