Debits after cancellation

I cancelled my cover with them. After this they still went and debited me twice. When I speak to them on the phone they say they will refund yet I still await a written confirmation thereof. Also, every time I do call I have to explain the same story over which makes we wonder how come their calls are not recorded . And if there calls are recorded why was I debited twice after canceling not only over the phone but also over sms and email.