Cancellation fee for what when the driver didn't even stop for me?

I booked an uber for my sister yesterday afternoon. Everything was fine, said Driver was 1 min away. My sister called me 5 mins later saying the driver drove right past her, didn't stop. I tried to contact the driver, but i was unable to reach him. I see that Uber has now charged me R25 cancellation fee. But for what? The driver didn't stop for my sister? He drove past the address, didn't stop, even after she ran into the road to flag him down. Driver cancelled on me without stopping...so why should i pay the cancellation fee? I am very disappointed Uber!