I won!!.. the same game three times

talk with giveaway creators. don't activate them.
ask for "reroll" because you already own it and let them open the ticket.
if it doesn't happend in the next 7 days, open a ticket for yourself and explain it to steamgifts support. :}

what vinirockman says :)

good thinking. don't be a whore.

that guy who created the giveaway not gonna respon or reply to us
i've won like 2 copies of the same game too, and over 1 month now still nothing happen !

Just ask the creator to reroll, add him on Steam.

Lucky bastard ;) But seriously You should give 2 copies back.

I don't think that's the only game you've won more than once

never click received until you have activated a key. Obviously you can't activate more than one. So ask for a reroll and mark it unrecieved in the mean time. Never ever regift it. If you follow this you will avoid a suspension and filling peoples blacklists.

Worth noting, since this looks to be related to the developer-created Featured Giveways:
In the near future this should happen far less, as per this thread: http://www.steamgifts.com/discussion/aJ8F9/changes-to-featured-giveaways