Doing an anti-virus scan is useful, KeyLoggers can steal your MC accountIf your account has been compromised this means another person has or had access to your account.
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