Duplicate key error - Someone freakin' generated my key

[Downward Concept]

So I recently just bought this PC and downloaded Steam because I couldn't even play Minecraft properly with my earlier PCs.

A few days ago I discovered that some old games could be activated with the key, so I blew the dust off of my old Half-Life game, typed in my key and got the Duplicate Key error.
This game hasn't been touched in a decade, so some ♥♥♥♥♥♥ generated my CD key.

I did some research and there is nothing I can do about it, can I?
There used to be a CD Key Reset, the Support used to do something about it, but now I instantly got the message from support that they don't do anything and Google tells me the same.

But I'm furious that generating CD keys seems to be tolerated when they don't care.

Is there ANYTHING I can do?!

[Cathulhu]

You could send them photos of the case, disk and key combined with the receipt to proof you are the owner of the license. But that would only get the game revoked from the account that has it.

I just would put HL1 on the wishlist and wait for the next sale. Or play the free remake Black Mesa:
http://www.blackmesasource.com/

[Downward Concept]

Already sent them a picture with my complaint. CD Case, Manual, Key, CD, Username, Date etc.
Of course I don't have a receipt unfortunately, because I had this game for like 10 years.

I am just angry about the fact that the only solution is to buy the game, when someone got it for free with pirating CD keys. What is the point of buying games then?!

[TirithRR]

Are you sure it wasn't you that used the key sometime in the past decade? Seems like an easy thing to forget about since you yourself forgot you had the game.

[mozarellajuice]

I just write this to get achivment

[Downward Concept]

Цитата допису TirithRR:

Are you sure it wasn't you that used the key sometime in the past decade? Seems like an easy thing to forget about since you yourself forgot you had the game.

I bet I did, but not on Steam and I don't even think the PC had internet connection back then.
Is it a duplicate key even when I didn't use the key on steam?

Edit: And I didn't forget about the game. I haven't had a PC for a long time and I thought I couldn't install it on Windows 8.1 anyways, but then I discovered that I could use my CD key to download Half-Life on Steam.