Thanks again, but yes it was a Toyota policy. I got the denial of claim letter from Toyota Motor Insurance Services Inc. and I communicated with them via email to firstname.lastname@example.org. Its Toyota allright.
One other thing I thought of is to take the dealers, oil changes stations, and Toyota Motor Insurance services all to small claims court. I think in Illinois you can go to $3,500 that way. However, I'm not sure if I can sue them all together or one at a time.
I think the first owner must have neglected the car and would be reluctant to admit that but I may track him down anyway. I wonder if he will own up to putting the hamburger in the car.