Uber Eats not giving me my change

I ordered food yesterday and everything was wonderful until it came to payment. I did not have the exact amount on me so I gave the driver R200 (the bill was around R168). I have never had an issue with this before as I usually immediately see the change is added to my Uber Eats/ Uber account immediately afterwards. It is now the day afterwards and I still do not see my change. I have contacted Uber and had no response. I also tried to call them and I cannot get through. This was not the drivers fault because he loaded it in front of me. He was lovely actually but I now do not want to complete the rating yet until Uber sorts out its nonsense. Please assist. I know it is not a large sum of money to most people but to me it is alot as it could be milk and bread etc, etc.