Still debiting after cancellation

After buying a vehicle from Thompson Motors Port Sheptone I was contact for a service plan which i took in July. However due to dealership error I cancelled this plan on the 18-08-2015 as the dealership has agreed to service my vehicle at their cost.<br> <br> I faxed through the cancellation form to the number provided of *** and received a fax confirmation that this form had in fact gone through.<br> <br> This service plan still is not cancelled. They debited me last month for this plan and my debit order is due at the end of this month. According to the company they have to record of my cancellation. <br> <br> I would like this policy cancelled and debit returned to my account as this was done after cancellation.