Permabanned for something I didn't do

So I woke up at 4am this morning because I wanted to study for my 8am final. I showered and made some breakfast, and then opened my email to make sure there weren't any announcements from the school or my professors about the exam. I've had an extremely long week, barely gotten any sleep, and when I opened my email this morning the only email I received was from riot. The email said my account was banned for illegal 3rd party use or altering of the client. I can promise you I didn't download anything at all yesterday onto this computer, and actually the last games I played yesterday during study breaks were on my other account, not even this one. So why does this account get ban and not my other?

But better yet, why are any of my accounts being ban for 3rd party use when I didn't use any third parties or mess with the client or whatever in any way? The amount of time and effort put into this account and now it's just gone, because of something I didn't even do??? I mean come on..... I believe this is my first time ever writing on the League threads because this is so damn annoying.

Almost every single game I've played for about the last month, someone on my team hard ints or griefs "because it's preseason who cares" so my games haven't even been very enjoyable lately, and now my accounts is just perma banned for something I didn't do when all these trolls never get any punishment besides the rare chat restriction... I've played League for like 8 or 9 years now, and this is seriously enough to make me never touch the game again because the punishment system is so absurd.