Thanks for the answers but now i found some interesting method to report these exploiters/hackers/cheaters. The following might be useful to the ones that don't know about it already :) http://nw-forum.perfectworld.com/showthread.php?306422-Reporting-Exploits-The-Right-Way And my apologies for not seeing this link before…
Hahaha lol :D...no seriously, the matter is pretty serious. They should find hackers and take serious measures. Also future hacking should be prevented.
I didn't think of taking a screenshot as i was overwhelmed by rage. But i'm pretty sure he was a hacker. 2 or 3 of us were hitting him with our encounters and nothing was working. And i don't think it's a graphical issue as with other opponents we didn't have any problem.