NO.

Sorry, I had to step out for a while.

Create a support ticket and let support know about the situation.

You should mark Received ONLY when the gifter gives you the designated game. Regardless of the situation, the gifter can NOT give you a "replacement" game. Regardless of what the gifter asks for you, you should NOT mark a giveaway as received unless you actually got it. The site rules are strict in this manner, and you can get falsely suspended over such an act.

If you like, you can talk with the gifter to get the giveaway deleted. This will require the gifter to ask support about giveaway deletion, and it'll require your confirmation (usually done by leaving a comment on the giveaway). Otherwise, you should keep it as Not Received for now.

I'll deliver the game you've won. Thanks for letting me know about your situation, and in the future, please don't mark Received just because a gifter asked you to.