I bought 2 downloadable copies of the expansion only. I received the codes to register them. the other acct registered fine but this acct i receive the following message.
BTW -I bought them through SE's store.

You cannot add expanded services because either the maximum number of service accounts have been added/registered or there are no service accounts to which the expanded services can be added/registered.

*If you have not performed PlayOnline registration yet and have a registration code that begins with U or if you have a FINAL FANTASY XI 14-Day Free Trial registration code, please select "Add new PlayOnline service account" and enter your registration code.

I attempted to contact SE tech support but it must not be working correctly. It will not let me send an email to tech support even with all fields filled out.

Thank you so much for your help.
Btw this acct was originally created in England but have been using it in the USA for several years now and haven't had any problem before registering codes.