Netstar does not care!

This has got to stop! I bought a car in 2007 and had a Netstar installed. I had a replacement system installed and it did not work. Netstar confirmed to me that the contract had been cancelled in 2014. I have been going through some very tough times and involved me going through my bank accounts and cancelling all debit orders that continued being taken off. I spoke to Netstar and they confirmed to me that the contract is no more. They owe me about R16,000 in incorrect deductions. I am being harrassed by a credit call centre for R560!!! I have emailed Netstar and not a single answer, response nor acknowledgement. Shocking and I am not the only person I know who is being harrassed so. Tremain Woods