Good evening I need to lodge a complain under checkers -Flamwood at Klerksdorp

Good evening I need to lodge a complain under checkers -Flamwood at Klerksdorp. I bought stuff amounting to R776.50. I paid with my Capitec card. The amount went through and the till did not produce a receipt and the teller rebooted the machine and I was told they have issues with the WiFi . I must pay again and I did that , because I was told the first transaction will reverse back into my account . I phoned the shop the next day on 5th of December and they confirmed it was a double payment and they get back to me and that never happened. I called the shop and spoke to the manager by the Name of Mical when i phoned again on the 10th of December. He promised to reimburse my money. And I haven’t received my money back. Kind regards Tiyiselani Nxumalo