Arf, from my understanding, there isn't exactly a way to resend an activation e-mail.
It is possible that the account was never created such as the registration closing before the account is made. I'd contact a member of staff, linking them to this thread and providing the username you have tried to create as well as the e-mail used for its activation. They should be able to get back to you on whether or not it exists in the user database.
Me hopes this helps!