It is impossible for anyone to gain access to a Miniclip account, or change its email unless that account is Facebook connected, as account changes can only be done by our Support team.
If someone else played using your account, we recommend you to change your password. Here you will find a link that you can use to change the password (doesn't work for accounts only connected to Facebook).
If your account is Facebook connected and your Facebook account is compromised, that is not of Miniclip's responsibility. Make sure to contact Facebook directly and ask for their help in reset your account's password or email.
Also be sure to end session of every device that is not yours right after changing the password.
If your Gmail is having an issue like this, you can always contact Google in order to recover a hijacked account.
Take into consideration that fact that we are unable to log out accounts from specific devices, so always remember to log out whenever you use a device that is not your own.
Once changes are applied to your Facebook account, they will automatically be applied to all games you use via Facebook.
Please remember that you are responsible for your account and you should not share the account details with other people.