I had this same issue. I used to work for GameStop, and I did so for total of 7 years before I had to find a better paying job to survive. It is because I used to work for them that I still frequent the store and do my pre-orders and such there. I pre-ordered in August and NEVER received a code and had to contact BW CS with a copy of my reservation receipt to get a code. They gave me one that same day thankfully and I am credited for December 2nd. Yeah it sucks I won't be in today, but the thing that really irked me about the whole situation was the lack of communication.
Back when I worked at GameStop, my store manager required ALL employees to read and initial all incoming e-mails... ESPECIALLY ones that deal with any pre-order bonuses since many issues stem from them and cause an unhappy customer base. I am sorry that this happened to you and any other GameStop customers. I still hold a soft spot in my heart for the company, but this taught me that the store I go to is not the right one and I have since moved all my reserves to another location that is farther away, but has a manager that seems to understand my plight. That is the only suggestion I can make to you and any other loyal GameStop customer. Don't let one really bad apple ruin your whole GameStop experience. They generally have good ppl, I used to be one =).