Oh god...this is the worst type of scenario! I really feel for you man. Those stupid teenagers. I hope they will at least feel bad enough to stop being so irresponsible. Don't count on it though. Man this kind of thing makes me furious!
Good luck man, I hope you can salvage some of the parts at least. This is exactly why I use Spektrum now for all my planes. I just don't trust the knuckleheads you run into sometimes