Talk to your credit card company... AmEx is usually pretty good about getting you home by any means if the airlines messed up. (especially if you hold more than a green card)
Airlines regularly overbook... ContinentHell is notorious for it... One of the things you learn early on with air travel.. there's a big difference between a ticket on a plane and a seat assignment on a plane...
I understand the need for overbooking to some degree - -but it shoudl really only be in certain markets (like the vacation markets where the odds are good that people will cancel or miss their flight because l ittle mikey didn't want to get in the car)
The travel horror stories i could tell would make Wilbur and Orville ashamed that they ever considered air travel