Contact Customer Support if you're having this issue.
The game's old installer and old multi-player system are incompatible with the modern Origin UI, so the key needs to be verified before they can add it on to your account and allow you to just download the Origin-revised Deluxe Version directly through Origin.
You will also need to either link your account to or create a "Classic Origin Screen Name" if you want to play the multi-player game.
Enjoy. ^__^
