Uber double charged me for a one way trip

I called up an Uber cab and confirmed (accepted) the one way trip cost of R21.00 and did my Card payment accordingly. To my horror, Uber had not only charged me for the R21.00 as per trip cost but also charged me R29.00 on top of my trip. It's shocking! Uber HAYKHONA! refund my R29.00 immediately !! I doubt I will use your service again, such an inconvenience.