non functional tracking device

I wish to say C track' s service is amongst the worst. In 2012 i signed a contract with them to have a tracking device in my car. It wasnt working for 3-6months yet i was paying every month. The device was removed and changed. A year later the device also stopped working. I informed C track on several occasions of the fault and they kept promising that they'll sort it out in their system but failed. Sometime early 2015 they could not track my car completely and at that point i realised my car was at risk of not ever be found should it be ****** as their system could not track the car at all. I called them and they admitted to their device failure. I asked for a refund and they promised to pay back R570 in July 2015 but even up to date that has not happened. Now i receive about 40smses for the wrong car being tracked of its whereabouts. Am seriously annoyed by this smses and wrong coordinates. I asked them to terminate my contract as it has ended and to come puck their device. Now they want me to pay for them to come take their non functional device. Seriously!??? Clients to C track out there, careful of C-track service. Your car might be ****** and never be found due to their faul