Encountering a premade team of non english speakers

I was just hopping into ranked to hopefully get some lp, i hop into champ select and some dude in the chat just starts saying some random shit it didn't look like any language iv seen before so i just ask if they could speak English they just went on with their language so i didn't mind. The game starts (**im playing ** )and the ** **that we have gets killed in the jungle twice and our adc begins to feed (1-12 at the end of game). Our top lane and mid lane were doing really good getting fed early on, around 15 minute mark starts to roam, came bottom lane and was diving their adc but their support was peeling really hard. Wukong fails the Dive and starts to flame me saying somethings along the line of "Fuck shield janna" "fuck bitch shield" of course the only time they would talk to me was to flame. Game gets to 30 minute mark and we're pushing mid lane and we got down some towers, then out of nowhere after that and just starts to feed for no reason at all, hasn't gotten a single kill at this point and does no damage with her sated devourer. starts to splitpush and gets killed 3-4 times doing it, on the other hand kept on blindly chasing their support and ends up dying a few times (she ended with 9-12). I tell and to stop doing what they were doing, then boom, i get flamed by the whole team. they barely spoke any english the only english they spoke were swear words. They start talking to eachother again in whatever language and then out of nowhere they start to throw on purpose. The game before they started throwing was 1-3 dragon 8-4 towers. So i just start asking what they were doing ,and i got no reply afterwards we lost. I really don't have any problems with people who dont speak english but the ones that just speak behind your back isn't cool. This issue has to be fixed somehow.

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