Key from LootBoy Supreme Steam Premium LootPack (PC/Int).
Seems to be working - i'm already own game and Steam prompts me to download exactly Ashes of the Singularity: Escalation.
But i'm not 100% sure. It's up to you to mark as not received if there any problem.
I don't like those kind of "agree to delete" BS giveaways myself and don't want to ask for that.
But game seems to be decent enough - don't want to just waste it.