Overcharged account on uber rides Cape town

I've been going around with uber for the past two days evertime the app gives us a price when we get there is a different amount we've booked a uber 2minutes before his arrival the ride was canceled and I was charged a penalty fee of extra R25 for a uber I didn't cancelled how possible this is a RIPP off to clients the last driver screamed at us when paid the amount on the app the next moment we checked the price has changed from R41 to R65 shocked at his reaction uber service suck