Debited for 15 MONTHS for a written off car!

Matrix was an awesome service. The app worked wonderfully without any glitches. I could track my car 24/7 as it was on uber and taxify. I even recommended them to colleagues and friends. In February last year my car was involved in an accident and written off. I was contacted by Matrix at 5am to notify me of the accident as they'd received a collision alert of their system. I headed to the scene of the accident and it was indeed a write off. I used their roadside assist service to tow the car awasly from the seen. This was obviously the end of our relationship. I notified them that the car was written off and I thus don't need a tracker anymore. They have debited my account for a car that has been non existent for the past year and three months!!! Every month I have to reverse the debit orders. Everytime I call and email there is no answer or response. When I talk to someone ovee the phone they are USELESS!! This is by far the worst service I have ever received. Why should I be paying Matrix to track a car that doesn't exist?!! For 15 months!