Continued Debit Order after Person Deceased

My Father had a vehicle insured with MiWay, it was full comprehensive insurance. When he sold the vehicle in 2014, they were advised to cancel the insurance. Please bear in mind that my father was 82 at the time. They then continued to debit him the amount of R 180.00 every month in case he ever wanted insurance cover with them again. They were informed this was not the case and should stop the debit order in 2014. My father passed away in May this year, and I contacted them again on behalf of my mother to ask them to stop the debit order. I even sent them a copy of the death certificate. They assured me the debit order would be stopped and also the debits of the last year and half would be refunded. Can you believe that they have continued to debit the account even though they have a death certificate, do they imagine that my father wants insurance from the grave. I think not. Repeated calls and emails to them make no difference.