I won this, but I received this message when attempting to activate it: The product code you've entered has already been activated by a different Steam account. This code cannot be used again. Please contact the retailer or online seller where the code was purchased for assistance.

Hi,
Don't forget to redeem your key and mark it as received please!

https://www.steamgifts.com/giveaway/SM403/raptor-call-of-the-shadows-2015-edition