Assassin's Creed : Revelations DLC - The Lost Archive

[ProTechy]

I bought Assassin's Creed : Revelations a year ago. Only now did I discover that I also have the DLC (The Lost Archive) installed along with the game. The only problem is, I can't play it. I open up the game, go to the Additional Content tab, but it asks me to enter a code. I have only one code, which I used to bind the game to Uplay. Will I have to download a crack or something to make the DLC work? I know for sure that it is installed. What should I do? Please help.
Thanks.

 

[James Mason]

Well, they may have installed it, but that doesn't mean you own it.

Blah blah, some BS about Ubisoft being greedy is the reason why, it's one of the day one DLCs that they "cut" from the game but left on the disc to sell you something you already possess.