No food no refund app order unfulfilled

I placed an order via the Nando’s app from the Nando’s Fordsburg branch, I waited for my food to arrive in what should have been an hour, the food was not delivered but almost two hours later I got a WhatsApp text from someone who said they are the driver from Nando’s and that my food was outside my door,I texted back telling them to take the food with them because I had left the building where I live to go buy food for me and my family,I subsequently got a notification that there order was delivered, I have since lodged queries on the app which generates reference numbers to say they will attend to my queries but nothing, I have tried to get a refund but still no action from them, I don’t know how else I can claim back my money as I paid for food that I never got and I’m left to wonder if indeed the delivery was fulfilled by their driver