How to deal with serious flaming

So last match I simply afk'ed because it was getting to be so stressful and angering because I was being flamed by my adc the whole time and I play games for fun, not to get flamed. To clarify it was not any fault of mine whatsoever that my adc decided to flash into their turret for a kill on a THRESH, and got hooked and flayed in. Meanwhile as sona, @ lvl 2 (for me) the only things I can do are q and auto attack and heal. The whole thing starts with "or don't engage..." when I used all spells available and landed as many autos as possible, what the fuck else am I supposed to do, I'm pre six sona?!!?!?!? The graves then continues to trade with the enemy when they are full and he is half health, and he finds the time to go back into turret to all chat that I suck. Then I get reported for going afk, I'm sorry but I'm not playing with a teammate like that, when I'm doing EVERYTHING in my power to help you as a support, and you flame me, I'm not gonna have that shit. Is there anything I can say/do to prevent this stuff? I don't want to mute the adc because we still need to coordinate, although its hard if they rage too much. If I really am so horrid, I thought they could try and 4v5 without me, cause apparently I "wouldn't help". What is the logic behind telling a teammate to "fuck off" and then reporting them for afk? This community is sickening sometimes.

The reason we no longer have supports or they are rare in teambuilder is maybe this, they get blamed when bot loses, its NEVER EVER the adcs fault. Meanwhile when I play with my friends we win bot lane almost every game, so I know its not me.

tldr; teammate engages stupidly, flames me continually for 10 mins so I afk and get reported for it (kind of understandable but not really). Don't flame your teammates. Any help to de aggro my own teammates? lol