Good luck in your Hunt, my son's passport was delivered to the wrong house, without a signature, where it sat for a month. The passport office kept fobbing us off until they could no longer argue why it was taking so long.
Apparently, it is OK for the courier to leave it without a signature , unfortunately the couriers need to be able to read, and determine the difference between the number 3 and number 2.
I have some escalation points if that helps, but as you are on site, I suspect you probably have all the right resources to hand.