Still don't quite understand the issue. I myself also have this game, and with both separate steam store pages - by having the one it shows on both pages I have it in library, regardless of it being classed as different games.
So to be perfectly honest I really think this user is being extremely difficult. Absolutely ZERO logic. I think it paints the user as being EXTREMELY ungrateful considering he did get the game 100% free.

But I created a Change Giveaway Game ticket... Please advise further.
For future though I think i'll reconsider this site and just not giveaway any free keys again.