An Interesting Dilemma...

Last night I was playing a game that was getting pretty toxic. I was playing a game as Mid lane, and the main Toxic person was our Bot Lane Vayne. Early on the enemy support roamed multiple times to mid and into our jungle and while this happened our Vayne and Sona did nothing to oppress the opposing jinx or even deny her farm. So after about 3 ganks and two deaths from the Enemy support Shaco's roams and the help of the opposing mid laner Kat, Kat started to roam bottom. I pinged but they didn't Respond and she killed them, she was getting Fed which good katarinas will do and she was pressing her lead. My own Vayne starts calling me a Fucking Retard (fking Retard to be exact) and flurry of other insults which I understand is extremely common in league.

I after a while got annoyed and responded (which i most likely shouldnt) by calling her a "potatoe Bot laner" then pointed out when your support roams to my lane multiple times you should be killing the solo enemy jinx or atleast denying her farm. Kat kept going bot and i kept pinging but she either had my pings muted or refused to respond to them and before we knew it we had a 9-1 Kat. Every time she killed the Vayne, Vayne had something nasty to say Calling me a Fking Retard 5 times through out the entire game as well as autistic and a few other nasty names. Never ONCE did i call her any name with a curse word in it (only the potatoe comment) but i explained in all chat that Vayne is getting Toxic and calling me a "Fucking Retard" At the end of the game I reported vayne and asked My jungler to do so as well. Turns out I ended up getting a Chat ban for typing "Fucking Retard" even though i wasnt calling anyone the name, but I was explaining what I was being called by my own Teammate.

Now I'm not here to try and reverse my chat ban because honestly it doesnt mean shit like 5-10 games where i just dont type much no big deal, But I would like to be informed by someone who can tell me does this Auto Chat ban thing just look for keywords and that's why Vayne was allowed to call me a "FKing Retard" multiple times and not get a ban, but as I explained myself I ended up getting myself banned for using "Harsh Language"? It's sorta lame to get banned for being using harsh language when I wasnt doing any name calling, but I was explaining what I was being called and why i didnt want to help my vayne when she was getting killed over an over. Sorry for the Wall of text and I would greatly appreciate some insight on how to avoid Situations like this aside from just not typing anything because that is sort of obvious.