Update. Turns out i'm the idiot. My wife neglected to tell me that they wrote down the mileage when they did the ESTIMATE, not when they got the car in for repair. I drove the car for a week after they wrote down the 'mileage in' (their words, not mine).
So that was a misunderstanding.
I took it in today and they apologized for leaving it filthy, took it back and cleaned it.
Unfortunately, the little cut they made in the steering wheel might be really difficult to repair, and a new steering wheel is exorbitantly expensive. It's really just a tiny little cut. I will probably just leave it alone.
The thing I was most incenced about was the mileage, but the it turns out that was just a miscommunication. I think they should write down 'mileage in' when you drop the car off, and they should write 'mileage out' when you get it back. They had a space for that, but they left it blank, which made me more suspicious. I hate it when I make an idiotic mistake, but it's better than if they had actually driven my car to King's Dominion over the weekend.