Cartrack Harassment

when my car was writtenoff i did notify the car tracker that i do no longer own the car it was taken by my insurence and ask the to cancel it but they dont want, now the telling me i am supposed to pay them R1800 which i am refusing cos i did notify the and ask the tcancel my service but they did cancel it and the staff is **** and bully i wont recomend cartrack to any one