[Valcrow]

I've had that pressure switch problem a few times with a few cheaper taclights. Like Johnny said, the connections disconnected presumably with the tugging of the pressure switch wire. The connections broken were at the cap where it screws into the tail end of the light. (my green laser works the same way) I just took that apart and resoldered it and it was fine.

What you could try to varify that it indeed is the switch and not your laser is if you have a taclight lying around, try switching the tailcaps (of they fit, I have a flashlight click cap on my laser for shooting stuff (spiders) around the house)

If you do find out, tell the ebay guy to send you a new pressure switch, he might consider that rather than sending you a new unit. And well, if he doesn't even do that, leave bad feedback and file a dispute.