Harassment. Please leave me alone.

I have been constantly harassed my multiple calls from two different numbers EVERY SINGLE DAY since the day I cancelled my services with cartrack. There was a double debit of R650 the very next day after an agreement was made of reducing the amount I was paying, from around R350 down to R229. I then decided to cancel the services and everything was well sorted out. A week later I started receiving calls regarding an amount in areas of R229. It has been close to six months now that I have been receiving early morning calls from various numbers, which majority of the time drop the call once I've answered. I believe this is now what I consider to be harassment and I'm seriously frustrated about all of this. I will not be paying anything to cartrack as I am certain that I no longer have any services with them, also considering the R650 that was debited without my consent. Please remove my details and stop calling me. Please.