Attempted redemption and how to improve behavior.

Firstly, I'm going to start off by saying yes, I am an extremely toxic player. I consider myself to be one of the worst there is in the whole game. A small excerpt from what lead to the perma ban of this account:

TRIGGER WARNING

"The Good Kush: meh, i quit when this autistic piece of shit nami refused to lane bot anymore The Good Kush: because i told her to stop going aggro The Good Kush: and let me farm The Good Kush: idgaf The Good Kush: you deserve it The Good Kush: worthless retard The Good Kush: go lay under a bus"

At this point I was down nearly 50 CS, 3 kills and my support was refusing to lane with me despite not acting in an inflammatory manner before hand, but rather requesting that she played more passive and allowed me to attempt to farm up so I could participate in the mid game.

I don't mean to be this way, honestly. I understand that people have bad games, and that's just part of life. There is always going to be a loser, and you can always play more games to regain your LP (except in my case where my account has been permanently banned and I lost all $700 of skins I owned)

I'm basically looking for tips to keep a level head in-game. After the game I can blow it off, but in the heat of the moment I can't help but go off on people. I've tried muting and that doesn't help, I still end up with a 2 week suspension or chat restriction for not communicating, which prevents me from explaining myself in a mild mannered way / congratulating my teammates / asking for buffs and as such leads to anger and eventually flame because I cannot properly relay my intentions.