What could I have possibly done?

I just got a 2 week ban on Monday. I have never been banned before. I've gotten a 20 game chat restriction once, but that is it. I randomly just got this ban now? 2 weeks? really? What could I POSSIBLY have said that deserved a 2 week ban? My best friend plays, he has been a toxic player for a long time and much worse than I am, but he always gets chat restrictions. He just got a 50 game chat restriction. The first time he got banned, it was for only a few days. Now Riot, WHY are you slapping me with a 2 week ban out of nowhere? Where does that come from? Have you thought about why there are so many players who are toxic and don't improve their behavior? Maybe your system makes NO sense. Giving someone a 2 week ban and another MUCH more toxic player a 50 game chat restriction.

Ranked is a competitive setting. People are there to win. When bad players are ruining the chance to win, and the enjoyment of good competition, other people will say something. If someone makes a bad play, it is perfectly acceptable to call them out on their bad play. If someone talks shit to you, it is perfectly acceptable to say shit back. We are not toddlers, stop giving out unnecessary/pointless punishments, and stop policing us. It is not noble of you to do this, its just a power trip, stop it.

Edit: on a more positive note on player improvement http://boards.na.leagueoflegends.com/en/c/miscellaneous/otOibPzE-hey-riot-want-to-improve-player-behavior