No resolution on cancellations

My husband and I recently switched life insurance providers from Old Mutual to another company. Because our bank was the sole beneficiary, they had to forward certain documents to Old Mutual. I sent cancellation letters for both my husband and myself on 24 June stating that the bank would forward the outstanding documents and that I would be stopping the debit order. Our bank faxed the documents on 24 June and Old Mutual claimed they didn't get it and proceeded to debit both of us. I have been in constant email contact with no resolution. I even sent the bank documents through myself. I have asked more than once for a consultant to phone me but nothing. So now I am paying twice for the same thing. I'm sure that we'll get debited again for no services rendered. Their email turnaround time is shocking and their lack of solutions is just as bad. I just want this problem fixed. Seems like cancelling with them was the right decision.