Accounts get reviewed. If they fail to comply with the "Terms Of Service" They can be suspended. There are also other reasons for being suspended.
1. Inactivity"Failing to log into the forums once every two weeks"(which is your case my4000)
2. Having multiple accounts
3. High resource usage.
and the list goes on.
To have your inactivity suspension lifted you can either lift the suspension yourself from the " Suspension Page"(click "check suspension reason" type in your cpanel user name and then click unsuspend now) or request the suspension to be lifted using the "x10" drop down menu located in the navigation bar at thwe top of the forums.