He either guessed the admin password, you admined him or a sever admin gave him admin.That's the only possible way he got to be an admin.
Nope, I always left the admin passwords blank in server options. Are all chatlogs stored in console.log?
Are you using his "hosting service?"
Yeah, this service looks real great. GREAT PING!
So now Pacnet2012 is denying the dedicated hosting service he did? Apparently that did happen so I assume that he wants to hide the dedicated hosting part of the drama.