Some excited gamers returned from the shops, clutching their brand new copy of Arkham City in sweaty anticipation, and, upon opening the game, found that there was something a bit odd about the DLC content codes that were meant to reward their early patronage. To put it plainly: Some gamers found no codes inside, some found multiple codes for the same DLC and some even found blank codes! Warner Bros are attempting to resolve the issue, but in order to do so they require customers to provide them with:
A new code will then be produced. Now, where did I put that receipt..?
Thanks to Joystiq for the info.