Account being banned.. not 100% why and how...

Okay. Someone please tell if this seems fair to you.

Im truly Confused. 5 years ago my friend and i shared an email for games, our local game store etc. We created an account on lol to try it out. I told him he could play first and try it out. He didn't enjoy it so i gave it a try. I really enjoyed the game. SO i started using that account . This was 5 years ago as i said. I was 11 at the time. Im now 16 and have been playing since. Ive spent countless dollars on this game. not to mention TIME. Last weekend, my friend got a hold of my password from a really old email account he some how remembered and logged onto my account. I had no idea of this , and when i logged back on that night, i was welcomed to a 14 day ban. I then contacted Riot Support, hoping to resolve things. I think the Support player was "Mama Meep" who contacted me. It seemed as it was going well. Then they wanted to clarify on what i had said which was " the original owner logged back onto the account and got the 14 day ban". I thought this was just to help. I then received an email saying that my account that i had put so much time and money into was now PERMA BANNED. i feel sick. Im fairly certain i'm perma banned for "account sharing" which isn't true. The last time that my friend( were not friends anymore, haven't been in 4 years) logged onto the account was when we BOTH created it with out shared email we used for everything. 5 years later i'm now being perma banned??? Someone please help. At this point i don't even care, you can give xXValenciaXx a 14 day ban or more. But a perma ban?Thank you that isn't fair. . I really don't deserve this...Ive been supporting this game for 5 years, paying for rp, playing games, recommending it to people etc...