First things first, multiple reports do nothing more than one does. It's like a True/False: Has this person been reported this game? If so, it gets reviewed - doesn't matter if it was one report, three reports, or nine reports.
Second, if you'd like us to identify why you were punished, please post the chat logs you can find when you log into your account. We can't tell you why you were punished if you won't show us the evidence Riot presented to you.
Lastly, please remember that others' actions do not give you an excuse to be toxic, troll, afk, feed, flame, etc. Each individual is held responsible for their own actions, and Riot gives you tools to enable you to fight toxicity without ever taking part in it (mute feature and reporting are the two biggest ones).