When nexon bans your ip, they static ban you. Mac changers, hotspotshield, dynamic ip changers etc won't help you at all. They banned your LOCATION, the means by which the government knows where you are.
Atleast thats what they did to me. All I did was email them and told them that I go on Combat arms at starbucks wirelessly and they unbanned me
if you hacked on another account, well you fail, want to keep beast account, get a shit pc and hack with it (just like i do) see my topic on the same section, you will be alowed it play combat arms again, to wait till you ask your isp provider to change you IP, the only way to unban you and be able to use no other programs, re-installing your system won't change your'e ip,