So in my inventory I have RHCP DLC that won't work with my EFIGS game.
Please, tell me if there's a solution for this. Or maybe we can trade DLC

I'd contact Steam support, they should be able to refund the money or if it was a gift, maybe deactivate the RHCP code and add the correct one to your inventory.

I did and they just told me it's a region problem. No solution, no offer for refund

Really? That svcks. I wonder why they can't change the region, there's no price difference (at least in Europe).

You can find the EFIGS version on Amazon (French site has all DLC, I believe). I don't think other retailers still sell DLC keys. Maybe someone here will offer a trade, but this forum is pretty dead...