Telkom debiting money even after cancellation confirmation.

I have had my contract for a few years and when I received my Sony phone I was asked if I would like to insure it for an additional charge. I agreed at the time. I later on wanted the insurance to be cancelled. I have struggled months to get it cancelled to save costs. A Telkom agent at the store than told me my phone payments will be completed earlier the year and the insurance would stop on its own. It did not. I have called the insurance company and spoke to an agent and they say they have cancelled it. I have received and email confirming that my insurance policy has been cancelled. Telkom continuously debits my account for the insurance. On Telkoms system they say they cannot do anything the insurance needs to cancel it on their side. Insurance has confirmed cancellation but every month Telkom still debits my account for the insurance payment. Telkom involves third parties for insurance companies but can not assist with cancelling the cancelled insurance payment from their system. I cannot block the debit order as my laptop that I am still paying is being debited at the same time as the phone insurance payment. I am fedup with Telkom taking money that does not belong to them. I will be cancelling all contracts with them and rather find a company that knows how to assist and are trained to work on their systems.