I'm a big fan of Uber, but the secret to dealing with cabbies is to be firm and obstinate. Like any street business, they're going to take advantage when they smell weakness and fold when they sense strength. Credit card machine doesn't work? Okay, here's the address where you can send me the bill. Don't try to stop me from leaving the cab, it'll be a big mistake involving police and you getting arrested for false imprisonment. Another thing I've done to much success is negotiate the fare to the destination up front, which prevents problems at the other end. Always remember that possession is nine-tenths of the law and that as long as you're in possession of the money, you're in the position of power. And when you act as such, you'll get more respect from the cabbies to begin with.