Question about the restriction/banning system

So I just got banned for 14 days without ever receiving a chat restriction, I find it very misleading to think you wont be banned until you at least had some form of warning, seems a bit ludicrous, considering how much time I put into this game. Sure I may have deserved some form of punishment for acting and or behaving toxic, but I normally am not so toxic, its just been these past couples days that i've been on edge because my fiance is away and I am just super easily triggered, normally when she's here I am able to keep my cool and actually try not to talk to toxic people engaging in a pointless argument. For example today I was playing a game where I was going Irelia and i went 21/8, my team wasn't doing so well, and that usually doesn't bother me so much, but when my 7/18 rengar, and my 5/15 yasuo start flaming at me blaming me for everything, "oh irelia wp farming top, noob lose us the game" after i literally pinged as many times as i was allowed to ping after pushing mid, I even wrote in chat "back up i have to defend top" because the wave was very large and would easily take our top tower. Then they continue flaming me and calling me bad and blaming me everytime they go in 1v5. Sure I got toxic and retaliated, but there were only a max of like 2 games where i was toxic towards anybody, I find it very unfair to have just out of the blue received a 14 day ban (especially because i have nothing to do while my fiance is gone) after no warning whatsoever.

But I will put that behind me and take the punishment and just suck it up because it was deserved (maybe not a 14 day ban for a first offense but still) My question is, after you have received a 14 day ban for example, how long do on average will i have to wait before receiving hextech chests again, and will it always be like the next time i even open my mouth to say something slightly offensive i will get banned permanantly or does it eventually decay so that you go back to the bottom for example like if i got restricted again after a year of no toxicity would i still be perma banned or would i receive another 2 week ban and or chat restriction. we all have those moments where we tell somebody to stop being an asshole for calling my mother's a whore and that I'm adopted and i was a waste of space, even the sweetest nicest players call somebody an asshole every once in a while. So if anybody could answer this for me or if i didn't even make sense at all just let me know.