When one person refuses to group/cooperate what do you do?

This is a a problem i find frequently in bronze, now i'm not saying that EVERYONE NEEDS TO BE MID let me be clear. This exact type of player has had me deranked so many times from bronze 3 to 4 (Yes bronze, I'm trying to get the fuck out.) along with other reasons of course. But this happens to be the absolute most frustrating and helpless situation. Unless your team is steam rolling the enemy and is able to 4v5 no problem, one person not helping when there is oviously a team fight going on s extremely problematic. My last game, i had a Diana jungle who would split push whenever the enemy team gathered mid and would take objectives whilst giving them kill gold by dying every time. In short all the lanes got a good amount of gold off of her, she happened to feed both the mundo (which i had kept under my boot early) and the mid zac, (my Mid actually lost to mid zac. I didnt really question it. It was just disappointing to know that we lost to a mid zac because apparently morg cant kite him ? lol) anyways, and the jax. Having a fed Jax, mundo, and Zac isnt exactly something people want in any scenario. We eventually started asking her if she could group with us because their team was grouping and winning each team fight because our blitzcrank kept initiating by grabbing and ulting the... tank...? She refused, of course, said the team threw the game along time ago and said to pretend that she didnt exist. Anyways, each time she saw that our team had been dragged into a 4v5 teamfight, she would run right past and "push" and then die. When they were going for the final push she did just that. And there was nothing any of us that are actually trying to get OUT of bronze could do. The worst part of it is that with how frequent of a problem this is in this division, there is no way for us to report them or anything like that. Even if it is in a way, AFKIng/intentionally feeding. I really feel like there is nothing i can do about this sort of player that i come across constantly. It's usually the jungler, on occasion the ADC. What the hell do you do about this? I'm trying to get the fuck out of bronze and this is just making it seemingly impossible. I REALLY would like guidance on this. Or just some sort of way to report them for it. I know that none of the players that do this get punished by the tribunal like most of the legitimate reports I've done because it to be honest (contradicting myself), isn't REALLY AFKing because they are "trying to get objectives" when they know damn well that theyre just doing it because theyve given up and dont want to afk in fountain so they do this to make it seem like they are playing the game when in reality they are just trying to make it easier for the enemy to end the game so that they can go unpunished for throwing a ranked game. Please someone understand, rito pls im praying to you (im joking), What the hell do i do about this frustratingly frequent player issue???? I run into this at at MOST after about 5 games. each and every day. I just wanna get out ;-;