Honestly, ignore him. How old is he, 9 yo, shutting the door at you like an ass?
Set up a camera working on your laptop continuously and start packing your stuff, making noise of course, provoke him to leave his "tower of sorrow", once he's out, your camera will pick up whatever he has to say.
Demand your passport if he refuses tell him that you're going to call the police because he can't keep you there against your will. If he keeps stand on his own, call the police. They will arrive and request him to surrender your passport and all documents you need. They even will be there until you finish packing and ordering a ticket.
All of this will be recorded by the time you leave.