Why is my account banned?

No ELO boost, no AFK, no toxic talking... I've been enjoying this game for nearly 4 years and I just played the game with my friends yesterday, we gifted each other several mystery skins, cuz it was my birthday. One weird thing happened last night was, my game client crashed when I was in the queue, and I logged back tried to queue up again but failed (i know it happens normally, and the client crashed like it used to be... ) I mean it's ok that the client crashes, cuz there might me a bug, or internet issue, or my OS's bug, etc.... But, why is my account banned today???? Yeah, one hour ago, I got an email said my account is banned. There is no reason to ban my account right? There are so many elo boosted players and toxic players. They are still playing this game right now, but my account is banned....... Why would you ban a loyal player's account, instead of banning those toxic players' and elo boosted players account?? I was even trying to help the game to have a better and more friendly community, but, it is so bm that my account is banned....

GG riot.

Update: they said my account was boosted... which wasn't... More info: I have two accounts, one is for practicing and one is my main account (which was banned) with almost all champs and at least one skin for each champ.. I had very bad performance for the past 2 seasons, so I decided to make a second account and tried to get better. Now I do have a higher MMR on my 2nd account since I can queue up with more gold players (yes I am not a skillful player, i am silver....) then I moved back to my main and finally I got a better tier than past 2 seasons. My friends told me that I can do better because my previouse MMR was too low. Well then, my main account was banned.............

Maybe I shouldn't say "GG riot"... I really love this game, and I do personally know people who get their account boosted... But they were not banned at all.............. But I got banned without breaking mmr boosting code......