Account was charged twice for a delivery

I ordered from Nando's Pretorius street in Pretoria on the 21st of September. The delivery guy came with a malfunctioning machine. He swiped my card a number of times without luck. he warned me that the receipt would fail to print because the machine was not working properly. Eventually he swiped and got a print out. However, I then got 2 emails notifying me of the 2 withdrawals of the same amount in my account. I didn't have cash on me. I called to notify them and struggled to get hold of the manager. Eventually I got a call from her and she told me she would check the machine and call me back when the delivery guy came back from his rounds. I didn't get the call from them. Today 27 September I phoned to follow up and twice I was transferred to an answering machine. They wouldn't give me the number for the shop or the manager. I then called the call centre who told me to go to my bank and get a bank statement so Nando's could refund me. I have been double debited, have spent a lot of time and airtime following up on my refund, however they still expect me to do the work of driving to my bank to collect my bank statement so I can get a 162 rand refund. if anything this whole process of following up has cost me more than they owe me already. Up to now, I don't have any feedback from Nandos.