Game disappeared from Steam Library

I had activated bioshock infinite(retail) on my account and finished it a while ago. I wanted to play again but I realized it is not on my library anymore even it is downloaded on my computer. When I click to the .exe file at steamapps folder it directs me to the game's community page. The game can be seen on my recently played games but the achievement section is not visible there. And in the licenses+subscriptions section, there is a steam-complimentary entry which I think is the reason of this problem because I didn't download anything related to steam at that date.(don't know if it is about beta though since I participate in beta). Also when I try to reactivate my key, it says duplicate key as expected and when I click "retrieve account" button, I get an e-mail about it. So, in a way it says the key is active on my account. I don't know what's the problem. I have asked it to steam support too but couldn't get a response for days. Have anyone encountered a problem like this before?