I'd say, give it one or two days more time.
Continuing the tournament w/o proper access to the bracket site can fuck up things real quick.
Take over the tournament on... let's say Monday if there hasn't been any sign of Panos but until then try to keep calm and relax.
I have no doubt the tournament will continue no matter what happens but rushing things now can end badly.
@Butan: your proof seems legit. I would still kindly ask you to keep trying to contact the dude. Every disqualification would be kinda sad, right? There is still time as long as Panos is gone...
EDIT: Oww, and in case Panos isn't back at some point, I'd suggest some moderator/admin simply takes over the thread and tournament. No big vote on that guy - just someone taking over and get the thing going again at a decent speed from that point on.