I got permanently banned for no clear reason

Today i tried to open my account but i was surprised when i found a message telling me my account was permanently banned which is pretty weird because i haven't done anything that break the rules so i checked my email and i found a message telling me 'Actions that have been performed on your account are in violation of the League of Legends Terms' i don't understand what wrong have i done to get banned the only mistake i have done was getting chat restricted twice and since then i tried to quit my toxicity can someone help me ?