I won the game, but I got the key for another game

never mark it received if you didn't receive correct game!

Might be best to contact the giveaway creator and let them know.

(oops sorry for misrepresenting)

Contact the person responsible for the giveaway. Maybe they put the wrong game in the title, or maybe they had keys for both and accidentally switched them up. Either way, you'll surely either get the correct game, or you'll get an apology and, should you decide to mark it Not Received rather than agree to delete it, a t least the the giveaway creator won't be blindsided by a Not-Received when it's likely they haven't realized the error yet. They've done 59 giveaways without issue so far, so I'd give them the benefit of the doubt that it was an honest mistake.

Thank you for advices.

If you mark it received but the game does not appear in your Steam account it's indistinguishable from winning and choosing not to activate it, so you can be flagged as violating site rules.

Company of Heroes was given away for free at some point so the giveaway creator wouldn't receive any cv for it anyway. If you ask the mods to delete the giveaway no one will have lost anything and you can still say thank you to the person who gifted it.

mark it not received asap and contact the gifter. let them know the game was wrong and they will either give you a proper key for the game you won, or ask for your consent to delete the giveaway. deletion is probably the fairest route here since you did get a game, just the wrong one.

most importantly though is marking it not received. you'll end up with a temporary suspension and future hassles for not activating a won game, since the key was incorrect.

As others have said, do not mark a gift "received" until the game that was advertised has been redeemed to your Steam library. Anything else you are given is on the other person, not you. This includes other versions of the game you were promised. When Support checks your SG account, we check to see that every game you have won here is actually in your library, so be sure you have what you were promised.

It is considered good manners to inform the creator of the giveaway if you have not received a copy of the game you were promised. The creator then has the option of supplying you with the proper key, requesting a deletion of the giveaway, or simply living with the "not received."

What Khalaq said.

When I was a young, fresh SG'er I had a similar thing happen to me. The key I won did not work, and when notified the GA creator graciously gave me a key for another game instead. I was happy, he was happy, and within a week we both got the shitty end of a temp-ban because we were breaking the rules.
GA creator for not giving the key to the advertised game, me for not activating the advertised win on my account.
So I learned the hard way, bought the game in question, and grovelled to moderators (it was sad really, all that begging...), and was finally ''unlocked'' again.

Do not mark as received unless you have received the game exactly as advertised in the GA description.

It is considered good manners to contact GA creator (as already stated several times above) and let him know there's an issue with the key.
It is considered good manners to allow the deletion if they can't provide a proper key - but it is not mandatory that you do so, it is up to you.
If GA creator gives you a new key for the correct game, all is good.
If not and you allow to delete the GA, all is good.
If not and you don't allow to delete, you then mark as ''Not Received'', and all is good.

Thanks everyone for the advices. Contacting the giveaway creator was really the right idea. He said he values his reputation, so he gave me another key, which turned out to be the key to the game from the giveaway. In general, the problem was solved, and in the end, I received a key from another game as a bonus))

hey thats me xd

i honestly wasnt aware of the fact that it was an incorrect game
According to my knowledge COH 2 key is what I purchased and created a giveaway of.
but accepting the fact that there was an error, I purchased a new key for COH 2 and given it to him/her. And yea it works now :)