PLAYING RANKED

Riot i got a little note because i got demoted a you said i could get a free win but i end up by losing because my team is shit and i end up having to try to carry but they just feed and don't help me. you get that note when you get demoted it says you are guaranteed a free win next game but that is bull crap that has happened to me 3 times and hasn't happened. i was in bronze 1 and i had to get 1 more win to silver but i had to some how carry my team and try to win can i get placed in a game with better people please or can you put me in silver thanks.!!!!!