unfair business practice and poor service

i have an account with tracker connect and it covers 2 vehicles.to be precise its a recovery plan. i was involved in accident with one of the vehicles 2 years back and i sold the the car as is to the car breakers. i kept on paying for it until i was hijacked of the other vehicle number 2 and they failed to recover it. until now they have not. on conversation with one of their consultants he made it clear that i wont be paying until they recover my bakkie. so i stopped . also i couldn't continue paying for this other one i sold seeing on the quality of service they where giving me. i kept on receiving their statement and i ignored them since i was told not pay. now i am getting calls from their debt collectors wanting me to pay the balance. Please is there where i can go to get help about this kind of issue.