Downloaded Amnesia: the dark Descent but no product key?

Ok so i downloaded the game of the Frictional Games store for mobile payments, downloaded it, installed it and now when i try and launch the game it says i need a product key (serial number) and as far as I know the download didn't come with one. FRUSTRATING. please help.Downloaded Amnesia: the dark Descent but no product key?
Either it came in the confirmation email when you made the purchase or you need to log into your account on their site to get it.



Then wait until it gets dark, turn off the lights, put on headphones, and proceed to crap your pants repeatedly when you play it.Downloaded Amnesia: the dark Descent but no product key?
If you purchased the game, contact the individual/company you bought it from and take it up with them. If you pirated the game, either learn how to pirate the "smart" way, or go buy the game.