Still no refund!!

I purchased some items at Pick n Pay Empire, I got to the till and I swiped my card, their machine said it was declined. The guy at the till then said that they have been experiencing some faults with the pin point the whole day and that I should try my card again. It went through the second time. Later when I got home, my bank notified me of a double charge, that the first transaction was a success too. I went back the next day to ask for my refund, the manager, Lesley, told me not to worry it will be refunded within 24hrs. Two days went by and still no refund. I then called them to notify them of the issue. The manager then said that I should give him my bank card number so he could call the bank to assist me. He later told me that the bank confirmed that it is true and that I haven't been refunded and I should send him my account number to make the refunds. He didn't, When I called to ask why, he says I should have gotten the refund by now and that I should call the bank to sort it out myself. I asked for the contacts I should call and he never responded, nor gave me any contacts. It is now three months later and I haven't heard anything from him or gotten my refund back. I am now ready to take legal steps on this matter.