I won two giveaway at the same time for the same game

Keep one, tell the creator of the other giveaway to reroll.

Well, it's the community giveaway, Ruzh Delta Z, does that change anything?

You can find lots of advice using the search funtion:
http://www.steamgifts.com/discussion/1MLqi/won-2-copies-of-same-game-on-same-day
http://www.steamgifts.com/discussion/6KpvE/i-won-the-same-game-three-times
http://www.steamgifts.com/discussion/WB1SX/i-won-the-same-game-twice-cant-get-a-response-for-creator
http://www.steamgifts.com/discussion/fwzrp/i-won-the-same-game
http://www.steamgifts.com/discussion/ZlI2p/i-won-2-copies-of-the-same-game
http://www.steamgifts.com/discussion/Ed7Kn/i-won-the-same-game-2-times-what-i-have-to-do-now
http://www.steamgifts.com/discussion/S4v4Z/won-two-of-the-same-games
http://www.steamgifts.com/discussion/x7urv/won-two-copies-of-the-same-game-what-do-i-do

All of these have been posted in the last month. And I didn't even post them all...

Oh, maybe I should have added this one:
http://www.steamgifts.com/discussion/8HtkA/what-do-you-do-if-you-win-two-developer-gas-for-the-same-game

Wrote a ticket to support, thanks.