So when you go to https://social.bioware.com/user_entitlements.php (while signed into your account) you're not seeing it there?
You usually won't get a code to redeem when bought from the BioWare site it should just add it to your user entitlements page (where you would also find the download link).
You can download it from the "BioWare Classics DLC" page: https://help.ea.com/en/help/dragon-age/dragon-age-origins/bioware-classics-dlc/
However you'll likely still need it to be registered on your account properly because you'll need to log in to your account on the main menu after installing it to authorize it.
