Netstar cancellation is ipossible

Despite having cancelled my Netstar when my vehicle was sold in December 2020, I am still being billed, 4 years later. I have had email exchanges with Netstar, their collection attorneys, providing evidence of cancellation, all to no avail. Email cancellation was done on 2020/12/26, 10:17. It appears they make it so difficult and cumbersome to cancel that you just leave it for the few R100 per month.