Is Uber now ******** People?

I requested an Uber for my mom yesterday afternoon (as I often do) for a less than 5 km trip which was quoted at R46. My mom paid the amount when she got to her destination.

I later received an e-mail that "Your driver reported that you didn't pay the full amount. -ZAR 110.00 will be due on your next trip."

This is a lie! I have sent e-mails to Uber and I get a response that the driver reported an underpayment of ZAR110! How??? The quoted amount was R46 and my mom paid it!

Why is the driver lying? Is this a ****? What recourse do I or my mother have?