If your account has been compromised then this means that your login credentials have been made available and your account is either being used, or has been used, by another individual. You have been banned so that your account cannot be used by other people that wish to hack on the server without consequence.
To get unbanned:
-Change your email address password
-Change your Minecraft password at Mojang.com [Do not use the same password as your email]
-Appeal at appeals.ccgn.co and explain the issue, as well as that you have changed your passwords
To avoid this happening in future:
-Do not put your login credentials anywhere other than the Minecraft client launcher
-Do not log into websites using the same credentials as your Minecraft account (Especially Minecraft-related websites)
-Ensure that your password is unique and cannot be easily guessed
-Do not tell anybody else what your login credentials are, even if they claim to have a good reason for asking for them
