Stuff gets mashed quite a bit.
The only thing I can figure is that the box got mashed on the belt and the stuff spilled out. Whoever recovered the box may have found the coffin and smoking tips beneath the belt and just thought it obvious they went together.
Normally they'll bag the box. Printed on the bag is the "We screwed up your stuff" message. The employee may have just been lazy and didn't bother bagging.
To assume someone "stole" two out of three coffins just doesn't make any sense at all, for about a million reasons.
In any event, it totally sucks. I used to insure everything, but I stopped. I spent so much in insurance that I could easily pay for a number of lost packages. Occasionally I do use it though, if something is exceptionally valuable and I don't want to take the hit if it gets destroyed or lost.
I hope it all works out for you guys!!!