Guild Wars 2

I got directed here to contact support from the Guild Wars 2 facebook team.

I signed up on the 07/11/2012

Hi, I recently got an email about inviting a friend to play for free this weekend:

Invite a Friend to Play for Free
Your guest will receive an email invitation with a unique serial code that will allow them to play Guild Wars 2® for free between November 15 and 18, 2012. Our supply of free trial codes is limited, so log into your Guild Wars 2 Account to send your invitation today!

However it says the service is ‘Not Available’
Image here: http://imageshack.us/photo/my-images/59/gw2s.png/

Just wondering how I can invite my friend, thanks.