I reached silver 1 twice and got demoted twice

Most of the time because of my teammates, they feed, flame, rage, don't want to hear tips and worst, quit. In one game support I told Leona who tried to 1v1 fed AP Cho, to buy some wards and you know what she said? Why should I ward we are losing anyway. Yep. Now in another game, I was STOMPING my game as Garen against Riven bot lane kept flaming our jungler and then our midlaner was in the base, didn't do anything and Riven was split pushing, I told him to def, you know what he said? "lol fk u" and quit the game. I'm tired of climbing silver 1 and then dropping to silver 2. There should be some kind of system, if you win your promos 2-3 times you will get promoted after you reach 100 LP and not playing another 3 games.