Tracking contract cancellation REFUSAL

I had a tracking contract with Netstar for 3 years counting from November 2017 to November 2020. I sent emails on 04/11/2020, 08/11/2020, 16/12/2020, 25/01/2021 first to notify them of my intention to terminate the contract and then to follow up on same. When they ignored after several of these emails i decided to reverse their debit orders. Guess what? They handed over my account to debt collectors. I then drove to their offices in Midrand on 13/04/2021 to see if this matter can be sorted and finalized. They promised to rectify this, I have a letter confirming this but even today I received another statement demanding payment. I REGRET TAKING ADVICE FROM THE CAR SALESMAN TO GET A NETSTAR TRACKING DEVICE IN MY CAR. If they care to verify, these are my reference numbers: CAS-***-V4T and CAS-***-P8M2, a very disappointed client!!!