Hello 
Just as a heads up, they do want to discourage “naming and shaming” in the forums, so we can all kind of keep that in mind for future incidents. If you feel you have evidence and would like to report someone:
CC_FANG wrote: »
(…) There hasn’t been a system for reporting user abuse set up yet, so you can use Nexon’s support system in lieu of that.
You can email Nexon at customersupport@nexon.net
Be sure to include the game title in the subject line, as well as the following information (if applicable) in the body of the email: Character name, server name, account name, description of problem, OS version. If you have a screenshot or video you can certainly attach that as well.