I won [b]u/Cozmo23's[/b] Destiny 2 Shadowkeep deluxe edition giveaway on Reddit. They messaged me privately asking for the platform and gave me the corresponding key.
As soon as I got the product key I entered it into steam to add it to my library. The key was accepted but I received a duplicate key message, informing me that the key had been used earlier and I could send an email to the current holder (which I did).
My first response was to inform Cozmo23 but he is yet to reply.
Please help!!!