idk what's up with that promotion, but I've never seen to be able to get it to work. I always get the same message saying "Sorry, Riot Girl Tristana will be back shortly."
Yeah it's an annoying bug, you need to unlike the FB page if you already have it liked for it to work, and even then you may need to retry it a few times.
Nice new Rengar profile theme lol.
Also a new champ is revealed already
http://www.surrenderat20.net/2014/08/azir-emperor-of-sands-revealed.html#more
I think his base numbers are gonna be really low cause otherwise he will be broken.