I’m not an itch.io representative, but I might have some useful input:
How long ago did you contact support? From what I can tell they are currently swamped, so you might have to wait for 4 days just for a “regular” support person to read your mail. If it requires an admin to look at it as well it would take even longer.
A possible temporary workaround, would be to send the keys to the owners directly - if that’s doable for you.
That being said… During the past month I have encountered a wide variety of users on itch. If the number of available keys is going down, maybe consider the possibility that the system is actually working and those people might either have troubles with using the system or are noticing a chance to get an extra key to sell or gift to a friend.
There’s a… “secret link”(?) I believe that you could use to test the system for yourself without having to buy our own game. If the steam key distribution works for you, then there’s a problem at those users’ end. If it doesn’t you could test around to see if you can get it to work on your own.
That’s everything that comes to mind right now. Hope any of this helps.