Beta keys are not allowed because they either do not give the full game or they expire before the official release.

Even though the key is labeled "for Beta Testing" is can't really be considered a beta key since the game has been out of beta for years.

Regarding this ticket, I will answer here since comments are disabled on user reports.

1. It doesn't matter when the key was generated. What does matter is whether it gives the full game or a temporary (or separate) beta access. Temporary Beta keys are normally revoked when the game is released. Some devs will opt to provide a seperave beta version of the game that can be owned alongside the full game. And some developers choose to not revoke them at all, in which case they are no longer beta keys no matter what the label says when activating since they give a permanent copy of the game.
2. You have the full game in your library, you can see it here and here. You can also confirm on SteamDB that this is the only entry that exist for that game. There are no Beta version that would be different from the full game.
3. I do understand the guidelines and, most importantly, the reason behind them. Beta keys, guest passes and coupons are not allowed because they do not provide the winner with a permanent copy of the full game.

Valid keys with the label "for Beta testing" are surprisingly quite commonas deveoplers will often opt to distribute those keys after the game as released. I have many games in my library that were added from keys with that label years ago. There have even been cases of games bought in stores or in bundles that we tagged this way.

Now that it's been established that Peikho provided you with a key that did activate the full game in your library, not marking the giveaway as received will be considered feedback fraud and will result in the suspension of your account.

Have a nice day.