If you mean the Steam keys, there should be enough (although I have never had such download numbers as now and have been doing double shifts on bookkeeping ;)). 
If you mean claiming the game on Itch.io? Then I am not very well versed in what could be your issue. By claiming the bundle as you likely did to get the game, as far as I know, it should be available in your library, which I believe is "having claimed" the game.

There should be a Steam Key button below the download buttons at page bottom.