My question involves a consumer law issue in the State of: Illinois

I left my car with the valet at a hotel in Chicago. My vehicle was stolen from the "secured lot". My car was left unlocked and keys in the car. The thief entered the garage by way of the lobby of the hotel then the hotel service elevator.

The valet parking service is not questioning their liability for the vehicle itself. However, they are not willing to cover the value of the lost personal items in the car. Now I understand that most valet services have a disclaimer on the stub saying that they are not responsible for lost or stolen items. However, wouldn't my car not being properly secured be negligence on the part of the parking garage? Therefore, making them liable not only for the car but for the contents as well.