Mastercare - Unauthorized debits.

Unauthorized debits. Policy cancelled in 2006. As of Dec 2017 , debit order reactivated and I get a call from a call center agent (Jan 2018) indicating he wants to update the policy. On informing him that the policy was cancelled in 2006, call center agent apologized and put the phone down. Debit order deduction has continued every month. I have had to put stop payments at my bank , reverse debit orders every month for the past 10months. This company changes the value by a few rands/cents to bypass the stop payment. When I asked the call centre agent to explain "if this policy is active , how is it you have not debited my account for the past 11.5 years. When I tried calling their offices , no answer. Debits are still continuing to go off ....