This is exactly why you don't use a debit card (or anything like it) for travel...
For future reference, get an AMEX and they'll watch your back like no other card agency out there.
Quit screwing around with the peons; ask for the regional manager and start mentioning the term "fraudulent charges" once they get on the phone.
I've had worse experiences with Avis (someone cliped the passenger door of my rental and Avis damn-well near tried to total the car off on my credit-card), but some royal screwups with Hertz as well. If you've got a camera-phone, USE IT; take pics off all sides of the car after drop-off and keep documentation a few weeks. You'd be surprised how handy doing both can come in at times...
