It doesn't matter what you think the instructions were in the e-mail. They are to be followed as structured in the knowledge base or you risk losing out on the promotion or the dissatisfaction of attempts for resolution through customer service. Invitation status has 3 stages. "Invitation Sent" > "Trying Game" is instant once their trial is activated. Revisit instructions w/ the invitee or call CS at 1-838-537-0898 if this hasn't happened. Telephonic and live chat support isn't available until Tuesday under SOE's normal business hours. Petitions might suffice until then, but I've been waiting 2-3 days for mine to get further response."Trying Game" > "You've been rewarded" takes 3-24 hrs.
If you think there's something to be known about this promotion, my posts covered it. I've already explained everything regarded how this program has faultered in its synthesis. The only questions I haven't answered are that: A. you can use the same credit/debit card you use to subscribe a new account, B. game cards from websites that deliver them instantly will work, C. the mount is heirloom and tradable between toons on the same account (and same faction if on a PvP server), and D. SOE's customer service doesn't have parallel standards in what they can afford you in providing a fix for this debacle.
I have heard of people who have tried having the subscription transferred to their account after they hadn't followed this linear protocol for the promotion, but this was something I was unable to accomplish for my two invitees who had made "mistakes" in their sign-up. So far, TSRs (technical support representatives) have claimed they were going to move the subscription to new trial accounts that had been activated "properly", but they are still on trial status even though their trial "subscription" had been extended by 15 days. They can't even claim their rewards and it's been 2-3 days.
Kiara, I hope you have enough initiative to confront those responsible and inform us of the results. 
My current, outstanding CS tickets are 090213-002330 and 090213-002202 (this one being erroneously tagged as "Solved").