My account was hacked and permanently banned.

I have been playing league since season 1, but recently I've taken a break from the game. One of my friends has been playing league for about a year now, and he asked me to play today, so I attempted to log in, but i was greeted by a message saying I was permanently banned for scripting, i tried to look into it by asking my friend to check if I've recently played any games, and there were two games which I never played, and my Icon was also changed. so I assume I was hacked because the only other person who knew my account information is my brother, and he has quit league for about 2 years now. i am not sure what my options are now, and I was wondering if there is any way to possibly get my account back.