Hi, sorry to hear than:( I bought it with this bundle https://www.fanatical.com/en/pick-and-mix/build-your-own-fantasy-bundle and region restrictions on this game is nowhere mentioned.
What can we do in this situation? Sorry, I haven't another key:(

In QA is:

What happens if I create a giveaway and the winner is unable to activate the gift in their region?
If you setup the giveaway with the appropriate region restrictions, and the winner was outside of those regions due to inaccurate information they provided, then you can request a new winner for the giveaway. If the giveaway did not have the correct region restrictions assigned to it, then one of three options are available.

You can acquire a replacement gift or key for the same game, which the winner is able to activate in their region.
You can accept the giveaway as being "Not Received" by the winner.
You can submit a ticket to have the giveaway deleted. In order for us to delete the giveaway, the winner will need to post a comment on the giveaway saying they agree to have it removed.

We may choose third option: I submit ticket to support to delete giveaway, and you, please, write a comment on giveaway whit agreement to delete. I'm so sorry.

By the way, where are you from, where you trying activate the key?

I see you marked as "Received" - was the activation successful?

Well, I didn't find any restriction on steamdb either https://i.imgur.com/Nf9B6LN.jpg . In what country do you try to activate it?

Oh, great to hear that!