Similar story about leaving the thing unlocked. Mate of mine does groundwork's for a living so his tools of the trade , usually a 15 to 25 ton tracked 360' machine is normally already on site for him to use each morning so in the back of his scabby car derived van instead of expensive tools lurks stinking wet socks , boots and the odd hi-viz jacket that is so dirty as to have become Lo-viz.
His van has been broken into on numerous occasions to the point where the rear doors are now secured by a bungee cord and he relies on the internal bulkhead to stop anyone getting to the drivers compartment - but often in these cases it is the contents not the van that is the target - Imagine his dismay may as his 'new' van arrived the other day only to find it has no internal bulkhead ! he is more peed off of the fact that he has to now lock his van than he is for not reading the description properly while shopping for it on line !
He is now shopping for a bulkhead to fit his van...on line of course.
OP sorry for the distress the scumbags bring to your door.