Outstanding Trip Fare

I requested a cash ride with Uber and reached my destination. I took out R200 and the driver didn't have change, I also had R50 and R20 extra, so he suggested I give him R170 and he will add the R10 to be added my next trip so I can settle the difference. To my surprise after hours of reaching my destination, I could see that I owe the last trip R183.

I raised a query with Uber through their app, which I personally think it's a waste of time, as I have not yet received any feedback from them and on their website it states that they will get back to you within 24 hours, it's now been 3 days.