Billing for a service after contract ended

<p>Tracker provided tracking services for my vehicle. I sold my vehicle and informed tracker in June. They provided me with a contract cancelation penalty ending my contract (adding a zero), which I then disputed. I also belived the contract has lapse and disputed this as well. I was proven wrong in September and comitted to pay the cancelation penalty. They have however kept on billing me monthly for tracking serrvices, which I wasn't receiving. While disputing this they keep on billing me for services not rendered. I have therefore paid for 5 months of tracking services not rendered.</p> <p> </p>