I got banned for what?

Ok... There was one champ select where my premade friend and I first joined the champ select and I said first "supp" and my friend said first "adc"..... There was one Janna that literally didn't say anything and she just instalocked Janna support.... I already locked in so I couldn't go top, so I've decided to go bot with my premade friend..... She didn't care so she came bot with us, trolling, not giving shields, assisting enemy team, and so on.... I said at the beggining of game "report Janna for troll" and nothing else..... Janna was stealing our experience and trolling us all the time and being toxic...... Enemy Lee united with Janna and one or two guys on my team and his teammates and they were laughing at me and they were supporting that Janna just because she helped them win..... They were toxic and flaming me and my premade adc and we didn't say anything ugly or inappropriate..... They were flaming me all the time and I eventually muted em.... Enemy Lee was very toxic saying "get life", which I responded "get gf and change inappropriate name".... So basically i wanted to report that Janna, but I only saw 14 days suspension..... And I repeat: I wasn't toxic at all, I was not flaming, I was not saying anything inappropriate, neither this game, neither games before that I think this is really a shame and I have nothing to do with this ban, cause 9 toxic persons (in my case 8) can unite against one person who has nothing to do with anything and that 1 person will get banned......