Go to My Account > Code Redemption > Code Redemption History and if it isn't there then it probably didn't activate.
Re-enter your code again and if it doesn't work go here and submit a ticket. Chances are they will tell you to contact the person you pre-ordered from but it is worth a try.
Best of luck bro.
REPUBLIC <Insomnia> @ EU
16-man Nightmare Raiding
Ranged DPS and Healers needed