Hello,
You are banned for the reason "Compromised account", this means that your account was used by someone other than you to play on Cubecraft. To get unbanned, simply reset your password at
https://account.mojang.com/ Once you've reset your password, you can appeal your ban at
https://appeals.cubecraft.net/ and fill in your Minecraft username - There you click "Appeal", then fill in the code given on your ban screen, follow the steps given if not done already, you will then get unbanned.
If you have any other questions or concerns, feel free to shoot me a message :)
-Locked.