Failure to refund for cancelled online order.

I placed an online order with Mr Price on 3 May. Shortly after I had done this (and paid) I received a mail saying one of the items was out of stock (why was it on the website then?) and I would be refunded. I immediately got back to them and said if the table was not available, I did not want the chairs I had also ordered and they should cancel the entire order and refund me. 24 days and 4 phone calls and at least 3 e-mails later I am still waiting for the refund, in spite of the fact that I have twice been told that the refund has been initiated. So Mr Price is earning interest on my money (and it's thousands of rands) while I have nothing to show for it. This is particularly irritating because the entire problem is due to their oversight in keeping an unavailable item on their site.