pay for the service that am no longer receiving.

Very bad service, paying for the car that i have sold and even today no solution. I have write an email to explain that i have traded in my car so i need to cancel as am no longer the owner of the car. i was told i cannot cancel and not even given another option. I wrote an email to ask if its possible for me to have the tracker cancelled on the car i have traded in and installed in the new car i have bought still no answer. it is very much frustrating deal with this company.