I had a similar experience amazingly with TSA at Dulles. The folks on the floor were as uninterested as ever, but they did give me the paper with the appropriate numbers to follow up (I had lost something on the outbound, and lost & found was closed on my return when I stopped at the TSA area downstairs).
You leave a message on the machine and they'll return the call IF they locate your missing item. I figured I wouldn't get a response, but I did and someone did me a great favor by picking the item up when they left from IAD, at a time the office was open about a week later. This was the Verizon broadband card that fits in the side of the laptop, so it could disappear pretty easily but they did hold onto it.