Oh. If you entered your code as soon as the offer was available, they lost your codes or something. e-mail them at
support@namcobandaigames.com, give them your code, date the code was entered on the site, your name, shipping address, and phone number. They'll re-ship and you'll get it in a week or so.
Also a bit of unfairness, people who entered in the code first thing get punished. People who forgot and entered later get rewarded by getting Vol 2 as well as 3, while those who waited too long or didn't know what happened to their order get only Vol 2. Shouldn't matter if you already got Vol 3 from the brigade though.