Help with advice

Answer is in the FAQ.
https://www.steamgifts.com/about/faq

"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."

I'd recommend explaining your situation to the winner honestly and asking if they would be willing to let you delete the GA (you can also ask if they're interested in another game you have & be willing to take that instead and let you delete the GA, or add them to your Whitelist & making some WL-only GA's afterwards that would give them better chances at winning stuff). I feel pretty horrible if I'm the winner when a key doesn't work and there was no warning in the GA description that the key may not work & the GA creator just doesn't care and tells me my only action is to agree to delete the GA. That happened to me once - which is why I feel offering a consolation prize is so important.

what all the others stated, thats why in future giveaways always have a safe blanket statement.

example.
'if this giveaway key does not work for whatever reason etc, please let me delete this giveaway with you, the winner stating 'i allow ReinerBraun to delete this giveaway since the key does not work'

Thank you all for your answers, will try to appease...somehow.

Best way is to:
contact with winner and explain what happened and ask for a agreement to delete. I had once such situation and winner agreed to delete GA. Of course there are some ppl which does not want to agree but there are also many (most?) kind ppl who agree.

Other possible actions:

• If someone does not want to agree you can offer other game if he agree to delete.
• I dont use this way to buy, but I saw bundled games are sometimes sold pretty low price on some sites. You can try to buy such copy
• you can just live with unreceived

Also for future GA it is good to check f.e. SG threads for a bundle. There are usually such regional blockade listed in the main thread.