I had a rude opponent once (some kid from Sweden) back when I just started on this site. I copied and pasted the exchange to a complaint e-mail and got a fairly prompt reply saying that they have warned this offender.
It is unfortunate that so many people can't "play nice," but if enough people complain about them as soon as possible after the event, there may be fewer and fewer of these clowns to deal with.
i have had a string of rude opponents on here, and i really don't know how to handle the situation because i don't take kindly to being insulted for no reason. one thing i have experienced (and i suppose this is a coincidence, because it is sort of regionalist) is instances with players from india. i want to be diplomatic here, but recently i have played a handful of games with players from india and they really aren't nice to me. generally they tell me to play fast (even though the clock is 30 minutes) and i reply with "no" and then they continue to tell me to step on it, or resign, or something similar.
also i have experienced people calling me a dumb american, a loser, or just being incendiary when i move or they take my pieces. i can't stand it, but at the same time i don't want to stoop to their level.
also i must say i'm a bit disappointed that i can't curse, even so much to say d am n or s h it. so anyway... not that i want to cuss people out, but that's how i talk to myself regardless.
conversely, i have played against some really nice people from around the world. why can't we all just get along?
Why can't you disable chat, which I do always after a very rude behaviour from a Pakistani. It is shocking & embarassing to know that many Indians were rude to you. But, one of the reasons for the same as I think is that the number of Indians in Chess.com is the 2nd highest. So, the number of rude Indians will also be high as rude people are there all around the world.
I think a worse indecent behaviour is to stop playing after playing, say 5 minutes in a live 30 0 game, which I experience sometimes from people all around the world.