Recquest for cancellation of a tracking device

Around September I sent tracker a cancellation recquest for the device in my car as I was selling it.Up to todate my recquest has not been done instead tracker continues to debit my account for a service i specifically indicated i no longer recquire. I called Tracker on numerous occasions and still the contract is not terminated.I am so disssapointed in Trackers incompentecy that is costing me my money. Last Time I spoke to Noshi who said it was my problem I did not follow up on my recquest and He promised cancellation fee will be deducted and contract terminated this has not been done instead I am being billed for a car I don't have..I am so disssapointed