Too many toxic players

I'm new to the game level 17 still playing normals.

So I join a game say that I want the mid lane no one says anything two people are fighting over adc one of them just suddenly starts wanting mid I tell him you can't just change your mind and try to take my role from me he just does't reply and picks veigar.

Fast forward to the game he comes to mid lane to duo it with me I tell him that won't work the xp will split and we will lose the game he just tells me to go top and I told him you can't just change your mind then try to steal my role from me he doesn't reply and we just keep duoing that lane. you might tell me that I should've filled another role but I can't jungle I don't know anything about it and the other roles where taken and I didn't want to ruin the experience for the others.

Later into the game there is this shaco dueling another champion both of them where very low but the shaco was clearly going to die so I killed the enemy champion he started flaming for supposedly kill stealing and said report.

then later into the game I make a mistake and started getting flamed.

I went AFK I just didn't want to continue the game with such toxic and unsportsmanlike players you might be thinking I am contradicting myself as I said I didn't want to ruin the experience for the others but that was before I found that each and every one of them was toxic.

So what do you think I should do I encounter situations like this quite often.