Cash refunds

I called an Uber from work to a rank in Johannesburg. I was quoted R251,and then R254. Kept changing. My uber arrived. By the time I reached my destination the charge was double,R487. I had to go withdraw the money to pay this driver. I later complained about it and received a response adjusting my fee to R257. R230 would be my refund. However this would be uber credit for my next trip. I have account details on my app,why am I not given my money? I need the money not uber credit. They claim because it was cash payment,it will have to be credited. How is this a refund?