Transfer to regular service - Unable to Invalid code

[FarelTheGecko]

I'm trying to get my friend into the game. He pre-ordered the collector's edition (PC) WITH Shadowbringers, and he payed in Euro, so it is the version of the game on his platform, from the proper region.

Sadly when he tried to put in the code on the "Transfer to regular service" page, using the code he was given in the email (a 20 digit one), he gets the message:
"Invalid code.
Please verify your registration code and try again."

Just so we're on the same page, it's that gray Shadowbringers page with the info on Early Access, the Baby Gremlin and the Aetheryte earring. He did redeem his 18 digit (6-3-6-3) code for Shadowbringers. The redeem site confirms that it's already been used.

He's very confused, because he did not receive any other 20 digit code. Looking over the Square Enix store, there is indeed nothing listed underneath the collector's edition itself. Shadowbringers has the activation code there...

We heard people say that he won't get access to Heavensward and Stormblood content before Shadowbringers comes out, but there was never any mention of the base "A realm reborn" content, so we assumed he'd be able to get in right now, however that doesn't seem to be the case.

Could anyone offer some help?

EDIT: Turns out that the Collector's edition does not include the base game, however supposedly my friend only needs the base game, cause Shadowbringers will give him everything. Here's hoping