Cartrack keep ****ming me even after I canceled my contract with them.

Canceled my contract with Cartrack 2 years ago. Every year they send emails and smses telling me I have defaulted and in arrears. I take advantage of their black Friday discount offers and pay a fraction of the R2650 that I supposedly owe. I request proof of them receiving payment and request they also cancel my contract with them. Nothing. Twice this has happened. Last payment being made last year 2024. January 11th 2025 I receive a message that I still owe R2650.