I went through a similar situation in Lihue Hawaii. I was charged $150 2 months after returning the family van for too much sand in the car. I protested to the CEO and VP Customer Service and they refused to do a anything, even though I've been a 20 yr customer and spend over $5K per year. They were unhelpful and uncaring. Then I told them I would be writing about this experience in my newspaper column. They said they would waive it, but I wrote about in anyway. They were not happy. From my research this is a practice that Avis and Budget has used in HI. Maybe it's been so successful they are bring it to the mainland.

And the suggestion above about complaining to the manager? Complaining will likely get him a bonus.