Tracker refusing to cancel my contract for something i dont have

I had a policy for a car with Auto and General which included Tracker installed on the vehicle. I was paying insurance the premium every month. I sold the car in January 2018 which I called Insurance (Auto and General) and cancelled the insurance with the car. Tracker started debiting my account since June 2018 which i didn't notice on my account thinking its tracker for the new car i purchased only to find out last month (June 2019) that I have been paying tracker the money for the car i didnt have as the new tracking company (Matrix) called me and explained that the tracker Ive been paying for is not theres which I decided to phone the bank and stop the debit order. I called the call center and requested for cancellation since Ive been paying a car that I dont have for the past year and a half which they declined since i blocked the debit order and i was told Im due for payment for the last month but I do not have a DIRECT Contract with Tracker so who has to pay who back here? Could this be another money making skeem?