Firek: Please open a Support ticket and send us the code. We'll look into it, but generally you should immediately contact the seller and request a refund anyway.
I would also appreciate it if you could send us a link to the exact offer you purchased the code from.

Kinguin, like many other key reseller sites, is not a partner of GOG, or CD Projekt. They are not authorized to resell our codes. I can't say for sure, but this is likely also the case for other platforms as well (as in - Kinguin and similar sites are not their authorized partners).

I'm not sure what kind of code you purchased - it sounds like it's a cheaprt, regional version, which can indeed only be redeemed in a specific country (or countries). Someone bought it for cheap, and resold with some profit.
Once you send us the code via a ticket, we will look into it. But you almost certainly have to request a refund for this code.

Once you (hopefully) get your refund, I would suggest buying the game directly from an authorized platform (ideally GOG;)). It's the safest way to buy games online.
As a general rule - if an offer is too cheap to be true, it probably isn't.