Netstar bad experience

You How must I go about. I have cancelled Netstar trakking because my car that has been ****** has n early warning tracking unit installed. The car has been ****** without Netstar was aware. My car has not been recovered and the so called bonus was not payed out for not recovering my car. So I cancelled my contrack with them for my other car that has the same device installed. They keep on putting the debitorder through against my account. I have to stop it every month.