GTFO. It's barely three months old.
Seriously, there's a definite stench of entitlement hanging over this thread. "Oh, I want this popular indie game that was released three months ago for three bucks!", "Oh, I will QQ if I get an automatic refund on a blatant pricing error!", "Oh publishers are ripping us off by not charging the same price on any website!". Please, just get out. (Especially the last complaint. There's literally no reason other than sheer laziness and your bank being dicks to not just buy on the cheapest site especially if the game comes in the form of a Steam key)