How is that Fair

I am positing this in player behavior because this has to do with the way people act in games. I could see this fitting into General Discussion a bit better, but there are circle jerks who stalk the general Discussion Boards and i am hesitant to post stuff there.

I have a question. As a support, when you work your ass off adn get your adc fed and you LITERALLY worked your ass off to do it, even taking deaths and shit, and she straight starts recalling after winning a lane fight with full everything and three + enemies down on the enemy team as soon as i return to lane after a death or something else (warding/etc.). HOW IS THAT FAIR TO GIVE ME A LOSS HOW?? Not only that but how is it fair to judge my MMR off a game where my kda is literally going to be shit because i ruined it feeding my adc who then threw it in my face and the rest of my bronze ass team can't stop yelling at each other or get off youtube long enough to actually play the game. My kda continues to go to shit because in order to support my team as sona I have to be open for getting picked off, and of course im the first one they go for because im the only one doing shit on my team.

I have this problem no matter where I go. For instance, adc i am winning 1v2 agianst my laners [ ](my janna is helping a little but with only an occasionally good tornado, she starts feeding late-early game into mid game) and the mid starts camping me. I then go on to 1 v 3 as my supp starts feeding, and they still cant handle me. I end up with top and jng on top of mid sitting and my lane and i cant hold tower any longer. This goes on for a good 5 - 10 minutes (or more i dont remember, but it felt like forever), mean while my jungler (who i qued in with and was in a voip with) was avoiding me BECAUSE I was fed, but he wasnt doing anything either. I am literally pre occupying the entire enemy team and mine doesnt do anything to help or make progress on towers. I am usually very quiet in chat and ping a lot ( I try to stay out of the chat box if i can, other than mias/etc. of course) as it tends to and has gotten me in trouble in the past X~X.

I am not saying i am pro, because i would easily loose to those more practiced than me (these are bronzies im destroying, not amazing tbh), but I am IMO proving that I can make better decisions than the rest of my team, so why am i getting matched with these guys still? Is the system that broken that loosing impacts your MMR SO much that you could literally be faker (or some other pro, I dont watch E-sports much, I just said faker because . . . memes) but if you loose a half of your games you will never improve your MMR. Like is there no definite way to "lvl up" your MMR and keep it there? This system makes me feel like a stupid kid trying to run up a slide backwards, you get so far then slip once and go all teh way back to the bottom, like where the f* did all my effort go?