To be threatened with being blacklisted for canceling a contract on a car I don't have anymore? Why would I pay fro car I dont have anymore?

To be threatened with being blacklisted for canceling a contract on a car I don't have anymore? Why would I pay for a car I don't have anymore? I cannot afford to pay every month for a devise that's on a car that was taken back to dealership due to it being faulty, I have no control over faulty cars. For cartrack to insist on me paying the R2,600.00 cancelling fee on a situation that has nothing to do with me, honesty its reaping people off. I can't pay units on 2 different cars more especial if I don't have the other car anymore. I will never ever associate myself with cartrack.