Account Hacked and Permanently Banned, but it wasn't me!

Hello,

My gamer name is ajsstarwars. I used to play lol a few years back with a couple buddies of mine. After realizing it was taking too much of my free time, I decided to take a break. Today, after having installed lol again, I received a notice saying that I have been permanently banned. It scared me for a bit, because they showed me three games, I don't know when they were played and they were not from me, where someone was playing my account using profanity and racial slurs. The only button I can click on is "I understand" and then the lol client closes. This was not me who typed these messages as I haven't even been playing for years and do not use such language! What do I do now? I had also quite a bit of hours back in the day and champions saved up on this account. It would be sad if I had to build that all up again (which, now I don't even have the time to do) If anyone could help me that would be much appreciated. Thank you!

-ajsstarwars