Someone please help me...

I've been playing League of Legends for going on almost three years now, I've kept up with eSports, I've been a huge fanboy and have loved the game forever now. I've had nothing more than a few "negative attitude" warnings over the course of the last two and a half years and as of yesterday, my account has been banned due to "3rd Party Modifications to my client". I've never had any interest in modding nor have I ever had any attempt to mod or to cheat on this game. I have no clue what to do, according to Riot's support page, a ban cannot be lifted one it has been placed, but I assure you, I've never done anything like this. Can someone, honestly anyone, help me or point me in which direction to go with this, I've spent well over a hundred dollars in RP on my account, I have months put into this game, not to sound like a loser, but I've dedicated so much time into this game and now I feel as though it's all been for nothing. I really need help with this, I'm willing to do whatever it takes to recover my account.