I Might Need Help Climbing

I can't seem to win by myself, no matter what I do or say my teammates find some way to throw.

At the Nexus Turrets, its their last one and all but 2 of their team is dead, we are all alive, what does my team do? 1 by 1 dive the Nautilus and Shen and all die leaving only me and Bard to take the 20% Life Turret, which we couldn't since Shen and Naut just went to heal then came back at full hp. Xin Zhao comes up 10 seconds later and teles into our base, takes a turret, inhib, and both nexus turrets because he was super fed and me and Bard couldn't stop him. We lose.

Next, we are way ahead and we win a bunch of teamfights but we never push or take any turrets afterwards. Udyr is always off by himself, gives up 3 free dragons simply because he is always farming somewhere else, and comes in late or goes in by himself and dies immediately. After a few 4v5's we are no longer winning teamfights... He continues to solo push while we are engaged on over and over again. He tells me i need to peel... They have Irelia, Kat, Quinn, and Kalista... I can only peel one of those, after that I can slightly reduce their damage but I am our only front line without Udyr so our Backline just gets wiped out. At first I could peel, I could tank all their damage and interupt Kat, but it got to the point where she was so fed she could insta kill Veig or Sivir and then they would converge on me and Raka...

I need teammates who know how to teamfight, know when to split, know how to take objectives, and know how to end the fucking game...