Oh wait, it gets better!

"Based upon recent suspicious activity, we have identified that your account may potentially be at risk. For your protection, we have temporarily suspended login access to this account.
Instructions for lifting this restriction have been sent to the email address registered to your Square Enix Account.
For more information about the login restriction, please refer to the following page:
http://support.na.square-enix.com/j/lbna"

This is what I get when I finally do get a download going and log in.

Thanks SE, you've really made me glad I've spent several hundred dollars on this game.