My take on the incident is somewhat different. I would think that the two individuals who knocked on your door pretending that you had called them were really thieves, if not worse. Their pretense that they thought you had called them was really just "social engineering," to get in the door (or to cover up being caught trying to break and enter). I would have called downstairs to the desk immediately and insisted they check those two out. Call me suspicious, but I think that explanation could be possible.