Complaint

I had a car tracker with them, in 2023 February i sold my car i paid their services up until November last year. I sent an email in October stating that i wont be needing their services. To my suprise January 2024 im receiving emails for default payments.. I sent about 5emails canceling my account, no one is coming back to me. I received a call from one of their agents i told them that ive sent through emails to cancel, she said she will come back to till today.I recently received final demand and that my account is been handed over. What i dont get is why they not responding my emails, they keep on send me the emails to settle the account.. I believe i have right to cancel at anytime why its taking them so long to do that while when i joined it was done in 5mins. I can't be forced to pay what i dont have, and i gave you the whole month in October to cancel my account.