Trolls Need Harsher Punishment

Today I was in a game as Yasuo and we had a Cho top and a Wukong jung. Personally, I find the lane matchup against LeBlanc for yasuo to be hard, but I won lane and I was pretty excited about the game. However, our mf decides that when I ask her to go to drag "she doesn't like me" and then, even though she herself was fed, went to base and bought full AP and trolled for the rest of the game. It's not like we were behind 20-1 and her team wasn't surrendering. We were ahead 16-3... I thought we could carry the game but the tables started turning and I went from 4-0 to 6-8 over the span of 20 minutes. I grew really frustrated and no matter what she didn't change her mind. We ended up losing around 40 minutes. What I'm trying to say is that league has a really good system for punishing people for bad language, verbal abuse, etc. However, I do not see nearly as many people banned for trolling! Trolling, in my opinion is a much more DESTRUCTIVE action. If someone is raging in chat do you know what I do? /mute xyz.... I can't do anything about trolls. You should not be affected by another person's immaturity to the point that you have no control over the game whatsoever and this is why I feel like Riot needs to truly take a step in the right direction... I have no fun in league anymore because, especially in normals, whichever team is losing is going to have one person feeding or trolling because they can't handle being behind... It's truly unfair and needs some attention ASAP.

tl;dr: Trolls need to receive more common and harsher punishments.

Thanks for listening to my rant, FlamingUber