Pathetic Cartrack

Good day, in February 2020 I sold my VW Amarok, and notified Cartrack that I no longer required their services as I no longer owned the vehicle. my "contract "with Cartrack had already expired, and up to the time that I sold the vehicle I was no longer on a debit order, but would pay the bill via a bank transfer. Since then they repeatedly hound me for payment, either Via email, or telephone or sms's everyday!! When I explain my story, all they say is that I must pay the outstanding, which is now +/- R 1700.00, and then I must cancel my contract again. What contract? absolutely rude and pathetic, never mind totally useless. I will NEVER do business with those Jokers again.