Uber please help

I actually wanted to choose 2 star but then I remember those guys at uber that are really doing a good job. When you urgent need transport and after booking it, it says 3 minutes and 15 minutes later they are still not there. Then they drive pass you and you get the message on your phone they canceled your trip. And sorry you can not really complain and you have no other way than giving the drivers a perfect rating because if you don't they ask you so much questions.