I have trouble Advice please. I can't contact to winner

Have you tried a comment on Steamgifts (old giveaway of the winner), on Steam and sending an e-mail?

If there is no response to either of those, you could request a re-roll (and in the re-roll ticket ask support to delete the giveaway).

Well, I would say you shouldn't have given away the game you didn't have. Lately I saw quite few giveaways which mentioned similar text like 'you have to accept the gift asap, since sale will end afterwards'. I think this should be prohibited by ToS.

Anyway, back to your original question - just wait for an answer. Did you try all 3 available communication channels? (here, steam, email)