The boss gone

I had encountered a boss at 6.15pm (16th June 2013), but when I enter the boss raid activity room, the boss is not there, I'm sure it is not defeated by any person as there is no boss essence reward given in daily rewards there, and there is no showing the time that boss being defeated. The same thing happens to my another id : kennichi875 ( boss met at 6.07pm 16th June 2013)

Both of the id are from server 28

Please tell me what I can do with that?

i can make you feel better and say that today i hunted like 5 bosses and none of them appear in my main acc spended so much hours for nothing