Insurance not being cancelled.

When I upgraded my contract, I requested my device insurance be cancelled. It was not. I requested again after a few months when I called into the call centre. It was not cancelled. Last time I received a sales call from vodacom, I asked to cancel my insurance and was given the number *** which puts you on perpetual hold. I am getting debitted every month for insurance that I cannot use because my sim card is not in that phone since I upgraded over a year ago!