Just block them. I wouldn't even bother to "fight back" if I were you.

you do not have to take that abuse. Respect is a number one obligation of everyone online. sadly we do not see this all the time. my advice? delete them immediately from your contact list and never accept their e-mails again. you do not have to explain anything to those "pigs" (pardon my expression).

The best solution is to cut off all communications. They just want your attention. Delete them, block them, or whatever. You don't even need to waste your time replying back.

when i usually say dirty words to girls online... they usually tell me to： 1. go to hell, you loser! = 去死啊你这个败类 2. get a life! = 你太无聊别再烦我 3. go sleep with your mother, you jerk = 王八蛋去跟你老妈上床 4. grow up you idiot = 你真是个白痴没有教育的 5. fuck off （请注意这是个很粗鲁的话）= 给我滚蛋 / 操你妈个逼 (use this if he's really annoying or if you're really mad haha) or you can do like most people here suggest... just ignore those type of guys, because many of them just want your attention. even if you say something bad back to them, they will enjoy it because they are 变态！always use good judgement, but also know your options... good luck! :P

Block or report (if serious). To talk back is probably what they want you to do, so save your time and just ignore them. Hope you find some decent people out there as well! An advice is to not have photos or user names that attracts the guys with dirty words.