If Someone Is Being Toxic/Bad Mouthing You
Do not respond, just continue to do your best.
Some people get bored trolling/flaming if the victim doesn't respond. It'll dig into their skin that they are wasting their time spouting slurs. (probably).
I had a game as support playing
against
. Been a while since I played support and yeah, I was dying a few times, not very successful lane. My ADC starting burning me with how bad I was and how I'm useless. But I didn't respond at all, didn't try to make excuses or retaliate. Toward the end of the game he actually apologized for being so angry before. We lost but everyone had fun in the end.
Sometimes instead of trying to quench a flame, sometimes it's best to let it burn out on it's own.
(just my experience)