Uber charging system flawed

Uber provides a good service, but their charging process is flawed. Pre-bookings doesn't work well Drivers and not optimal income, immediate bookings more profitable for the driver who is in the area at the time. This is not explained to clients. Recent pre-booked driver, 15mins late and still 24km away didn't take calls. I had to cancel to book a new trip and got charged R100. Disgrace!!!!!