Unauthorized debit orders for canceled policy

I have had endless problems with Old Mutual. Canceled my policy in Jan 2020. Old Mutual confirmed this cancelation but they have still been debiting my account. Canceled the debit order but they refuse to refund my money. I have been told that my death benefit for my life policy is still active as I didn't request to cancel that even though I have showed them the confirmation for cancelation email. The same premium is being debited. I try to explain to them but I get 1 line feedback and I am going back and forth with them. I need my refund asap.