On the PC, there are multiple ways to buy Far cry 4- you can buy it on Steam. You can buy it on Ubisoft’s own uPlay store. You could buy a retail copy, if you actually still have a disc drive. You can even buy it from EA’s Origin.
There was another way to buy the game- by purchasing a game key directly from third party storefronts like G2A and G2Play. Both G2Play and G2A are fairly popular stores, and both are based out of Hong Kong. Both get their copies of the games by “[picking up] all game codes/keys… through major distributors, from their original retail boxes, and scanned up into [their] database.”
But now, it appears that any copy of the game bought from either of those storefronts is mysteriously disappearing from user’s libraries on uPlay. Multiple users appear to have raised the issue on Reddit and on Ubisoft’s own forum.
Ubisoft’s response has been to tell users to contact the seller of the keys, which… I mean, that just seems to be implying that the fault is not Ubisoft’s at all.
We’ll keep you posted.