I'm sorry to hear that you too had stuff stolen off a truck at Indiantown. About a year ago I had a bunch of engine parts stolen off a Deuce I won there.
The coincidence here is that I also had H&S Towing pick up my truck and store it until I could get there to pick it up.
I hate to say it, but GL is going to tell you there's nothing they can do for you. You appointed (hired) an agent, H&S Towing, to retrieve your vehicle. It was incumbent on H&S to make sure that the truck was in OK condition before they signed for the truck. Once they signed for it, GL is effectively relieved of any responsibility. That is exactly what GL told me when I contacted them about my missing items. I hate to agree with GL, but they are correct on this point.
The fact that stuff was missing from your truck SUCKS. I don't know what we can do to get the thefts to stop. I would agree that we, as buyers, should contact the base Commander and Law Enforcement of the bases EVERY TIME things get stolen.