this is why you should always pay for rental cars with a credit card(most will even allow you to put the charges at the close of the rental on your debit card)... I worked for a rental car company for almost 6yrs and I have heard even worse stories than that.... It is also alot easier to dispute charges with a card that doesn't tie up your actual available funds...
I know there are alot of people that try not to get/use credit cards, but this is a reason you should have one, for emergency and rental car purposes....
but yeah, you need to talk to the regional manager for that location and con him out of a free weekend rental or something and buy the full coverage ins. and rally the sh!t outta that car and take your aggresion out on them there..