If you did they survey that they send out they should have sent you a coupon yesterday. If you weren't sent a survey to complete then you're out of luck unfortunately!
http://www.videogamecoupons.org/exclusive/videogamecoupons-org-exclusive-get-60-off-over-80-popular-games/
Some pretty good deals here, they had a similar sale back in August.
Doesn't matter how many active monthly users they have, there is rampant click fraud on their advertising platform. Advertising on facebook is almost worthless.