Bad customer experience

I had a credit card with African Bank, last month I then decided to pay it off and cancel my credit card. They assisted me and I received a sms confirming that my credit card has been closed. This month on the 23rd, a debit order of R750 went off and it was African Bank, I phoned them on the day and they advised me that a refund request would be done and that I should expect my money within 24 hours. I have not received my money, yesterday I decided to call them again and I spoke to a lady by the name Bongi, she apologized for the inconvenience and promised that I would receive my money in just few hours. 8 have not received my money and today is a holiday, I cannot get through to their contact centre. I have a 2 months old baby and that money I have budgeted to buy my baby's stuff. I do not want to go to the bank to reverse the debit order because that will mess up my credit record. Please assist