While we do apologize that the system is giving you some difficulty, unfortunately this forum is not the proper avenue for discussion of such issues. This forum is for the discussion of technical issues with FINAL FANTASY XI itself, and not anything related to the account management system. In order to recover a Security Question and Answer, you will need to contact the SQUARE ENIX Support Center directly.
In regards to your preorder and to why it is saying the code is expired:
The release date of Seekers of Adoulin is 3/26/2013. However, the actual launch of the servers is on 3/27/2013 0:00 and any codes will not be able to be registered until then. The Destrier Beret is an item that already exists as a bonus from the Ultimate Collection Abyssea Edition, so you should be able to redeem that code right now. If you preordered Seekers of Adoulin from the SQUARE ENIX Store you will need to contact Digital River for support at
http://www.digitalriver.com.
The SQUARE ENIX Support Center for North American accounts can be found at this link:
SQUARE ENIX Support Center