Any time there is an issue on the main site, such as stolen art, harassment or or site bugs or account problems. Use this link (found in your User CP) http://www.furaffinity.net/controls/troubletickets/ to fill out a trouble ticket. You will get a faster official response this way, and it saves on unnecessary drama and posting in the forum.
Change the drop down box to the appropriate Issue type, Fill in a description of the problem under "Message:" and make sure to be accurate and detailed so that way the problem can be found and dealt with in an efficient and correct manner. Then hit the submit button.
If there is any issues an administrator will contact you, and after the situation has been satisfactorily dealt with, they will close the issue.
(Did I miss anything?)