Still Awaiting Refund on Double-Charge

Last week I bought KFC for my family after placing my order online for collection. When I got to the window (which was probably only 3minutes after I placed my order online), they said that the order hadn't shown up on their end yet. No problem - the manager asked me to park, which I did. About 10mins later she came outside with my order, which was great - the only problem is that I was double-charged. I told the manager and she said that the money is usually instantly refunded when there is a mistake. The incident was 30 January and today is 3 February - no money has yet been returned to my account.

I understand that this wasn't intentional however, I have emailed KFC 3 times since and, as yet, have not received any type of response.

Please advise how this situation can be remedied asap. It's a very small amount of R124.90 but, during the pandemic, that is a lot of money to my family and I.