What should you do in this situation?

ARURF game mode, nothing special. Champ selection. Enter game. And so far everything looked fine. (Just one guy talking a bit too much but we all ignored it.) Then after noticing that she was fighting morgana as a syndra, she decided to leave lane. Which I just make a notice, "just because you fight morgana you switch?" But then nothing came back. And I let it go. But she started attacking the team every time the turret I was trying to protect, by myself was about to be destroyed. And every time I died, she would ping me many times. Say I suck and that some other people in my team sucked.

I made a mistake to not mute her early. She started to really show off to the enemy team just because she was "Good". At some point I simply told the enemy team, ignor her she is just an a**. Not a good word. Could have said worse. But she did started to get a bit annoying.

And the best of it comes now. She started saying to the enemy team that she was sorry for my attitude and that they should just ignore me. And use many different text to blame me for something she was doing... What do you do in this situation? Especially that the enemy team could report you when you actually worked hard to get your honor up and that you are like the least person to get on people nerves...

Anyway sorry to have made you read all this... Now I m feeling... like there really people who would manipulate and try to look nice when they are just evil. (makes me think of teemo... cute outside. deadly inside...)

Edit: Looking at that player background.... Platinum 5... People at that level are really like that? If yes then wow I want to stay were I am with my small silver 1.