Dangun X

I keep getting "emails" in game from people trying to sell me power leveling. I'm pretty sure this is against the ToS. Is there a way for me to report these people or something? Maybe I didn't look hard enough but I didn't find anything about this on a site as to what to do. I am not even sure this is the right forum, lol. Point is, I'm trying to get these people to leave me alone for one. I've already sent them replies tellin them to f' off but they keep on coming =( Any suggestions?