Help me help the community

I just received a 14 day ban on this account for intentionally feeding, and would like to do everything I can to not get permabanned. I don't start off being toxic in game, I only get toxic in response to other players being toxic towards me. The reason I intentionally fed is because I decided to play Fiora, a champion I am very new to, in normal draft mode, and our jungler asked me to first pick Camille for her. I did so, and a few minutes later, the game started. I was against a Renekton, which I found to be a somewhat difficult matchup. I had given up 0 deaths even though I was ganked 3 times by the enemy Rengar, and about 20 cs behind Renekton. I had almost solo killed him once, but he flashed and got away. At about the 15 minute mark, I asked Camille for a gank, as Renekton had been overextended the entire game, and would soon have my turret destroyed. When I requested a gank, Camille quickly responded with "go fuck urself fio." That pissed me off quite a bit, and I flamed a bit. I then said I would afk if I didn't receive a gank in the next 2 minutes. I didn't get a gank, but the enemy Rengar ulted and he and Renekton killed me under my second turret, to which our 0/3 Ezreal (Camille was botlane the entire game, no idea how Ezreal was 0/3) said "trash fio." That's what kind of snapped me, and then I sold all my items, bought boots of mobility and 5 dark seals, and I intentionally ran into the entire enemy team. Later on I sold all of that and bought a sunfire cape and thornmail, and would just stand still in toplane until the enemy super minions would kill me. At the end of the game, I was obviously reported, and a few minutes later received a notice for a 14 day ban. I'm fine with that, I deserve that punishment. However, I don't want to get banned again, so I was wondering if there is a setting that completely disables chat, because whenever I mute my team, I get tempted to unmute so it's easier to communicate, but if I get flamed, I flame back, as I find it hard to just not respond. So yeah, is there a way to disable chat completely? I don't want to get permabanned on this account.

NOTE: I am not trying to justify my behavior. If anybody acts the same way I did, they deserve at least a 14 day ban. I am trying to stay reformed, and I think the best way for me to do that is to just not have to talk to anybody, especially when I just react to toxicity with more toxicity. If you ask my friends, or just most players I play with, I am not a very toxic player. I'm normally pretty easy going, especially when playing with a friend. But when I'm just playing alone, and some random player flames me, I can't help myself, and I flame back, or just throw the game. I don't want to ruin the game for the other players, but in the moment, I just get super pissed and don't care.

FINAL NOTE: Besides how to turn off chat completely, can someone link me to the page that gives the details on how the punishment system works? I heard that I can't get seasonal rewards now, or chests/keys, and that if I get reported again, I get permabanned, but if I don't get reported for 3 months, my status goes up a tier or something? Thanks.