repair costs for tracking device constant phone calls being received

I had to repair my tracking device as it was causing damage to my car’s battery and every Monday struggled with a car that wouldn’t start. I made a booking for the repair of my tracking device and immediately made an arrangement to pay the R600 repair costs via debit order monthly. It has now been almost two weeks and Cartrack keeps on phoning me daily regarding payment arrangements for this repair costs. I have now on numerous occasions confirmed the payment and asked them to stop phoning me and still receive calls at 7 am each morning! I am considering cancelling my services with Cartrack