Being billed without a contract

I had a car which is no longer in my possession for the past 9 months. The car had tracker, this was pre-paid for three years and no arrangement or any other contract was signed to continue with the payment once the pre-paid had expired. What also amazes me is that tracker is aware that the car was sold but they want me to pay.<br> I AM NOT GOING TO PAY FOR SOMETHING THAT I DID NOT RENEW THAT CONTRACT FOR, ESPECIALLY THE THE VEHICLE IS NO LONGER IN MY POSSESSION FOR THE PAST 9 MONTHS.