ACIII FE DLC Code Expired

[MadMan5]

I just got round opening my ACIII FE Collectors Edition AUS and the code for Benedict Arnold is valid until March 31st 2013 as this is the case now I feel cheated as there is no where I can find this information untill it was time to play the game all the other codes work fine.
My point is if codes are only valid for a small time can this be put on the outside of the packaging.
Maybe a DLC code list that has kill dates for games on playstation so that the information can be shared.
Is this a Sony PSN issue or Ubisoft I'm just not sure why codes have short kill dates as some will die in a year or so not every one plays games as soon as they come out.
Looks like now I have to go and have a look at all the dlc's I have for games and redeem them if I can and in the future.
Just want to know is having the information to hand important to collectors.