Old Mutual incorrectly debiting account

I am unemployed and had to unfortunately cancel my Dad's life cover because I could not afford to keep up the high premium. My husband and I both have life cover as well with old mutual. Even though I took out cover for my Dad long after taking out our policy, I was debited for both premiums in one debit each month for years. Since I canceled my Dad's policy in December, I have been incorrectly debited for it at the end January and Twice in the beginning February along with my policy despite having been assured that my Dad's policy was canceled and that I wouldn't be debited further. I should only have been debited for my policy. There is no money in my account as I am unemployed so the money hasn't come off, however I need to put money in for other things but I am afraid that the total INCORRECT amount of R9000.00 would come off. I phoned so so many times, and the customer service agents assure me I should not have been debited for those amounts. So I asked for those debits to be immediately stopped and no response from them via email or phone. I tried to call all day and can't go through. I have been dealing with Robyn, the customer service agent and she has not bothered responding to me. I need these debits to be canceled once and for all and to be debited the correct amount just for my life cover. CAN SOMEONE PLEASE HELP ME. Has anyone else experienced such terrible service from Old Mutual?