Unauthorized withdrawal from Absa Credit card

Absa Credit card division withdrew money from my cheque account twice without my permission although my method of payment was eft transfer which is done on a monthly basis. Due to this large withdrawal my account went into depleted funds. My debit orders were returned unpaid. I have been requesting refund from 1st February and to date I have not been reimbursed although I have been told that I will be given back my money. I can't understand the delay as I am an Absa client. I will suffer further unpaid debit order bank charges.