After a couple of frustrating hours trying to get into Room 213 on Hotel Dusk (Nintendo DS) with Jeff shouting “I’ve got nothing to talk to you about” each time I knock on the door…… I finally worked out what to do after reading various cries for help from other people also stuck (in forums)…

Go back to room 215, get the 20k out of the suitcase, then go knock on the door.

How frustrating!