some cars do get damaged BEFORE they get sold as new.Yeah CarMax tried to screw me,I had a mustang with 56k that I bought from the original owner who I was with the day they bought the car new.Went to carmax to sell it,they offered me 2300 bucks and tried to tell me the car had been totalled and had been on frame machine.Sold the car for 7500 the next week and never have or will deal with carmax
when i worked at carmax, i saw several people get really pissed because the car they'd had since new had obvious signs of paint work.
I don't know if that is your situation, but it happens alot more than you'd expect