Uber overcharging people, what the hell?

For the past two days I've been overcharged three times. When you book a ride you expect to pay what you booked it for right, not almost twice that. Well it happened to me, I booked a ride and it said R45 but when I got to my destination it showed I owed R60 what the hell is that about and it happened again yesterday afternoon and last night. Oh last night was supposed to be R37 but again when I arrived at my destination I had to pay R51. Stop overcharging me, why for the past few days did this happen??? I'm not very happy about that.