How to teamwork in ranked?

Okay, so I haven't been playing league all that long (about 3 months), but my friend taught me and I'm now in silver III. Basically, I need advice on how to play a game with people around my ELO. I'm having an issue with them because basically people in this ELO seem to always want to fight. If I'm playing mid if I ever leave my lane midgame to go farm, my team will get mad at me for "not being there" for a fight, but the thing is, the entire game after laning is just trying to fight at or defend at mid. In normals I will get maybe 250 cs in the course of a game, but in ranked I will get around 150 because my team refuses to let me farm. Every time I go somewhere other than mid I get "we lost the fight because you weren't there." Maybe I'm missing something, but isn't it their fault for engaging without me? Also, it seems the enemy team always manages to take advantage of the death of a player on our team, while my team seems to just continue whatever it was doing when we get picks. I'm not trying to teamblame here, though. I realize that if this is a pattern in MY games, then obviously I have to be the one doing something wrong here. I just don't know how to fix it. Maybe I'm farming at inappropriate times or not taking initiative to make plays. Does anyone have experience with this kind of situation. I would greatly appreciate some advice so that I can start to win more consistently through team coordination.

PS: I do use pings to indicate if I am going somewhere to farm, but normally what follows is spamming of "assist me" pings. Should I follow the assist pings or just continue doing what I believe is appropriate?