Accounts keep getting 7 day bans !

Hello.
I wanted help because every time i try to log on to CF with any account it automatically gives the account a 7 day ban/block , im not using any of the hacking programs.
I would really want to know why it does this to my account ...
Until now 4 of my accounts have been blocked for 7 days and this is my main account and i don't want to get blocked , so please help ?

thanks a lot