You are much better off giving them a call. There have been some issues regarding the registrations not properly getting into their system, so lots of folks have been unable to get either the free X2 upgrades, OR the X2 Content Club's free DSP Strings Expansion pack.
I called the tech support guys - was only on hold for a couple of minutes, and they fixed me right away, by generating and sending me the download links for both X2 and the expansion pack.
They are additionally working on fixing it within their system, but in the meantime, just give them a call and will get you squared away.
Bob Bone