I'm not sure what else to offer at this point. Steam support isn't a phone line. If you did submit a ticket to them then please send the conversation from there so I can investigate further.
I'm not giving away another key, please look at this from our side. If players just said that they lost their keys and we kept honoring it, we'd just be giving away our work for nothing, or for resellers to sell gray market keys. I've tried but you haven't provided me with anything that can help me track down this problem.
You claim to have lost the original email used, ok understood, we recovered your key and sent it.
Now Steam reclaimed your key for some reason but you also lost any kind of log documenting a conversation with them or any kind of info message about the key?
We've only ever deactivated a single key that was part of a refund once. This is what it looks like on the back end for a deactivated key.
And this is what the key we sent you in the last email says currently. Activation time lines up with the same email exchange we previously had.
I'm not saying it's impossible for Steam to revoke a key themselves. I just have nothing to go on and their support is the only option at the moment for recovering your key.
https://help.steampowered.com/en/
If your steam support ticket was recent, it will be here as they are supposedly deleted after 60 days.
https://help.steampowered.com/en/wizard/HelpRequests
The only other thing I can think of is that maybe if you're based in Germany, Steam blanket banned NSFW games there several years back and maybe keys were suddenly made unplayable? If so then unfortunately there's no way for me to bypass Steam in that aspect. We have had German players activate direct keys with no issues and they have been able to play the games, with only the store page being whats unavailable.