Waiting almost a month for a refund!!!

There was a double payment made on my account on the 29th of July. On 31 July I called the call centre to arrange for a refund on the double payment, I was told that the refund had been processed and I should receive the funds within 3 business days. 3 business days came and went so I called again to enquire only to be told that the refund had never even been requested but that it was now escalated and I will receive the funds within 48 hours. This went on for days and weeks and I have called and begged and pleaded 20 times and I am still waiting for my refund! It's almost a month later and about R1000 worth of phone calls (at my expense) and I still have not received a cent! I finally thought I was winning with them on Friday when I was assured that the Financial Manager was aware of the situation and that he was personally going to make sure I receive an immediate transfer.... It's Monday and I still have not received ANYTHING! I am fed-up to say the least! I have been very patient and understanding but this is just past the point of ridiculous and its completely unacceptable!