unauthorized debit date changes

African bank debits my account without consent on a day not agreed upon by me. Now they do not want to refund me the bank charges that I had to pay. They requested copies of my bank charges statement which I've emailed four times since 24Feb and was advised that the process takes 48 hours (2days) its been 9 days and today they tell me I have to wait till Monday as the person dealing with refunds is not available today. 1 person out of the whole of African bank deals with refund requests..... Really? Guys please check your bank statements regularly as they debit your account without consent and then refuses to pay the charges you incur.