The thing is, you can't use the registration code of the game as a bonus item. The registration code is used for registering a "Service Account". The "Enter Bonus code" can only be used for registering items like the Onion Helm, the Cait Sith Doll, etc. If by any chance you have used the code from the Guest Pass leaflet, instead of the Booklet, then the chances are that you have registered a Standard version instead of the CE version (of which the code was mentioned on the backside of the booklet).
In that case, you need to contact the Support Desk about this issue. Which you have already done so according to your OP.
