Enterprise rental a car Accused me of damages I did not commit! Ruined my credit! Apple Valley, Minnesota

Where to begin... My husband rented a car through enterprise in august or september of 2009 on an insurance claim while our car was being repaired. The first car we had ran real rough, so he exchanged it immediately. The second car ran fine. We had it for just a few days, and we went everywhere together doing this time. We returned the car late at night and put the keys in the drop box. My husband then entered a school of discipleship in another state where he had very limited phone calls. Over a month after we returned the car I received a notice in the mail saying we owed over 500 in damages. The damages were on every part of the car possible and we did not cause any of them!! As a former employee of Avis rent a car I know that they are required to walk around the vehicle to inspect it upon drop off, which no one did as it was late at night. We never got a call or complaint until the letter over a month later. I explained to them this couldn't be resolved until my husband returned home. They sent it to collections!! When I called again to dispute it they told me I couldn't prove it and I told them the same thing. This past month (Feb 2011) my husband called them and talked to a supervisor who said she would look into it and get back to us. We haven't heard anything. We dont know how the damages got there but we did not do it. This is the result of an employees negligence to do their job properly and on time. Judging by all of the reports I've read on this same issue this company scams a lot of people. The worst thing is it's affecting our credit! I guess the only thing left to do is contact the bbb and hire an attorney... and because of the credit I well be suing for compensation as well as having the debt removed!! Worst company ever! They dont even return phone calls!