Originally posted by Owns
Not exactly.
Technically, Activision never said the game wouldn't be worse on PS3, and they didn't say there wouldn't be lag online, and as long as you can actually find a game then online is still, in the eyes of the law, playable.
The only way you can get a refund for the game is if the person at the store who sold it to you specified that the PS3 and Xbox versions are of the same quality or that there isn't any lag online, then you can threaten to sue the store for false advertising, or, if you're in Australia, Misleading and Deceptive Conduct.
The reason you can't get a refund legally is because the only way you would be able to is to threaten a law suit for False Advertising, however, False Advertising doesn't incluse lying by omission, which is what Activision did by neglecting to mention that the game was worse on PS3...
So don't just barge into your local game store and demand a refund, because Activison aren't legally responsible for providing you with one.