Disappearing - Reappearing Contract

I want this contract cancelled and i want everyone to know how underhanded Car Track behaves. <br> <br> I originally took up a Car Track contract through my insurance company. When I sold my vehicle last year July i cancelled my insurance with the understanding that the Car Track would be cancelled as well. Since i wasn't contacted in the following 6 months i felt sure that the contract had been cancelled as well. <br> <br> However this year May Car Track sends me 2 Invoices, 1 for payment for February to April 2015 and 1 for May 2015 out of the blue and now demand payment. As well as debiting my account for the May invoice (where they got my account details or authorisation?). Surely after 6 months of no billing i can safely assume that a contract has been cancelled? <br> <br> And now they expect me to wait another month for this contract to be cancelled, thereby incurring another months worth of fees.