chat banned for nearly no reason

so i was in a game right, was playing zed and feeding because i wasnt doing so well. suddenly the vayne on my team starts flaming me for inting and such. she tells me that the game will be better off a 4v5 and that i should afk. she also says to report me to the enemy team, right after telling me to afk. so, instead of feeding the enemy team more kills i farm in jungle and in lanes for a few minutes and catch up on farm. then when i finally decide to start fighting the enemy again i do well in the fights and play a lot better because i farmed. after we won the game the vayne said this: "report zed for inting, toxicity, and for afking". this made me think "well, i won't get any sort of ban because i have played many games and maybe i messed up a lot and get reported, but it isnt equal to the amount of times ive played so no ban". ofc i was banned but also keep in mind it may be because i joked around in chat saying "omg im gonna afk farm now that you told me to afk" and i did for 2 mins but then came back into the game. at one point i fed the enemy one kill purposely because i was tilted, but i didnt do that anymore right after. so why was i chat banned? i understand that game that i did a few dumb things but none of which deserve a chat ban. maybe because i responded to the vayne with logic??