I never played the game before, but i gotta say it's great ( not perfect, no game is ). The amount of dedication you guys are showing is inspiring and the fact that you are paying 4,700 dollars monthly shows it. The problem is that NCSOFT might close these servers as a example for others, because financialy these servers aren't hurting them, but it might lead to the creation of GW2 or Lineage 2 private servers ( or more of them ). NCSOFT only really cares about the Korean market so COH isn't an issue for them because the game was never really liked in Korea ( They like anime like games or lolis and stuff ). Honestly I would be really disapointed if these servers are closed, so you maybe wanna consider taking servers in Russia or China, both of them kinda dont fucking care about the whole private server thing ( especialy if if these servers cause problems to a company in South-Korea).
In conclusion, I hope you find a way to keep this project alive and would really apreciate the appearance of a donnation system, I woundn't mind giving you guys like 20 € per 2 months to keep this game alive.