Cartrack contract done, but still being debited.

I had a 3 year contract that started in Sep 2019, the contract ended in Sep 2022. The car that had the tracker, was traded in 2021. I then paid a full year without enjoying the benefits. When contacting them and explaining, the said I should send an email confirimg the contract cancellation. Which I did. I even went onto their watsapp group and explained time and time again. But they still keep on debiting my account. Can you please assist.