There are many many countries out there that are better alternatives to work in. Thailand is an option. Although there was a recent remark about never working in Thailand by another poster, I think comparing most countries to China would make said country look like a better alternative.
You can either avoid the Chinese experience altogether, or you can go there and deal with the Mancunian types. You deserve better if you respect yourself.

Thailand is nice, the Thai people are nice; they must be, I can hardly go five minutes in Bangkok without being invited to games of ping-pong by complete strangers. On the downside the temperature gets a bit much sometimes, as do the mosquitoes. Also, just too many packs of temple dogs around; they will even attack you on your moped as you pass by. If they do there's a big risk of being bitten and falling foul of hydrophobia-that'll make you irritable and froth at the mouth......have you ever been bitten by a dog,Dragonised...not nice?(Hyenas not included; bitten by your own kind, most unfair) I wonder, if you get bitten be a Chinese, can you get Chinaphobia? hahaha. I have been bitten by a few of my students, but touch wood, I'm still okay.

Mancunian: read... I did not wrote this chinese... The one named Hazel Yin.. she wrote this to me. [edited]
我建议 永远都不要来中国。
中国人的 俗是，付钱的人说了算。

Oh, China Man, she blurted that out to you(in a letter/e-mail) did she? I assume she felt she needed to put you in your place. I still think what she says is in itself reasonable; but on the other, hand you may well have beem making reasonable demands. Do you think that you can clarify things a bit for us and give us your side of the story in detail ,please; that would be helpful if you want to nail this woman? What happened exactly, please? Cheers.

Stupid ass agent named Hazel Yin... who is so fool of herself. Bad English , lots of misspelled words. If foreigners won't work in China, She has no income at all. She said Don't come to china... Once and for all, why don't we boycott China? They treat us bad.. low salary... give no due respect. Better go to some other countries.

She is a bad example of Chinese CORRUPT PEOPLE WHO FOOLED FOREIGNERS . Government should know about her.... spread this out... put it on weibo.

Thank you for providing a translation. I had found the following translation in Bing Translator (http://www.bing.com/translator): "I recommend never to come to China. Chinese custom is that paying people in charge." but I had understood it to mean that the teacher has to pay the Chinese people who are in charge (bribes, etc).
But you are right in your interpretation. And the advice is good too.

Cheers, Curious-wow, maybe you are more correct than I. But sure we have made a fair job between us.

This agent should be avoided. No respect for foreign people:
我建议 永远都不要来中国。
中国人的 俗是，付钱的人说了算。

Well, the nitty-gritty, you have put in Mandarin, Chinaman; I am only a beginner but think I have the gist of what you are saying. You say "I suggest you never, ever, ever, come to China-the people who have the money [have the whip-hand] make all the decisions." Quite frankly, Dear Boy, that is how things should be-no? If I employ a bloke to decorate my lounge, quite frankly, I don't want him deciding on the colour plan, or the wallpaper, now do I? 我的对的还是我是对的 - (am i right..bla bla.) Cor blimey learned that in the nick of time-full marks for Pimsleur!