Definitely hold it against them. 

Just talk to the students/their parents. Tell them to tell the agent that they found another teacher and will no longer want his services. Then, they pay you 400rmb/hr, and life goes on. 

In my experience, Chinese don't actually expect duplicity from foreigners (I have had idiot private students try to short change me, then hand me 1000 rmb for classes in advance). The sourcer might actually supply more students for ages until he gets a clue. By then, your friend won't need him any more. 

My philosophy is to deal ethically with people, until they have proven themselves scumbags, thieves, and parasites. I have no problem screwing over screwballs. 

I stop everything and walk away.

Other party can threaten whatever they want, lawsuit, suicide, ... I won't come back.

What Iverson should have done when those two scums were exposed.

But it should not happen if you do things legally and have a written agreement, a friend of mine finds students for a training center and gets 33.33% of the fees paid by those students, they have a written agreement with ID card/passport numbers of both parties, fingerprints and all, if he finds out they ripped him off and has proof he can probably sue them for all the embezzled money.

Fool me once shame on you, fool me twice or more shame on me.

Well, I've learned to keep your emotions in control and not too lose it in situations when someone try to rip you off just because you are a foreigner... I never dealt with the students and education so I have no idea about your example, however recently I moved my apartment and had trouble with the agents when they refused to pay me back my deposit from the previous house (i used the same agent for last two houses), so they made the excuses like -- you stayed in house for too long (I rented another house from them which they never told me I won't get well past my contract end date) also they made few excuses and finally said we lost our customers because you didn't give us the key (I was very clear on this- told them give me my money and i will give you the key)... these gents don't speak English, the only way to communicate is translations via wei xin... from past two days I was chatting with them most part of the day, and asked few somewhat demeaning questions like (I'm not proud of these)... why is it difficult to do business with you, why can't you honor your promise, what image do you project of Chinese on foreigners and things like that... It did work, they paid all my money back, I guess once you find out you are been ripped off, deal with it with a calm mind... Helps!!! 

Well, my wife responds to being ripped off by going crazy. She usually scares the hell out of the vendors so they give in to whatever she wants. I respond by arguing or just walking off (never coming back) and telling everyone I know. I will call them "cheats" loud enough for others to hear and make them lose face if they don't rectify the situation quickly. Of course, if they took my money beforehand, I will lose it and intimidate the hell out of them.  But to be honest, not many people try to rip me off. If you can speak Chinese to the point you can complain... you will notice a huge reduction in Chinese trying to screw you over.

When my wife and I are together... usually my approach is done first (maybe the clerk screwed up, maybe the store made a mistake)... when that doesn't work... my wife will get angry, shout at them and threaten to tell all her friends/family and the mall management (pretty well connected in our city so it would have a significant impact).

Just the other day, we ordered some furniture for our new apartment. It arrived and was clearly NOT what we ordered. It was even a different brand, the quality was much lower and the box even look beat up. She freaked out and called the store threatening them... 

They told her to pick a new dining table and the other items they would send in a week. She said "I want that dining table (upgrade on the original) for half price because you messed up." They were like, "But we will lose money if we do that." I replied, "You will lose a lot more if your store gets shut down for obviously trying to cheat customers."

So we got the better table and won.

China needs to stop treating customers like idiots.

How's that 'being ripped-off'?

Example: 'Guy said (to me too in Jixian, Hebei): 'I have many students, who want to learn English. Would you teach them, and how much is your pay per hour?'

'My hour is 400 Rmb.'

'Would you teach them for 300 Rmb?'

'OK, I'll teach them for 300 Rmb.'

Later, you found out guy is charging a lot more than you.

You are 'big ben'!

But, yes I would fulfil my promise, and then I'd walk away.

Public Schools I'm working for often try to rip me off. I usually resolve matter with 'enter SAFEA in search above'. 

Latest rip-off: School gained authorization for FT hire' at the later date then when they had signed Contract with me last Sep. In the process, they've burned my valid RP, and I had to exit China, and applied for new Z.

School purchased exit ticket Bj - Lon, and further to my home. Later, when I got new Z, school purchased tickets Lon - Bj, and G train Bj - Zhengzhou.

We extended Contract two weeks ago, and I asked for return ticket refund. School replied: 'We gave you refund already. You can't get it twice!'

1. Contract state, I will receive refund of return ticket home at the end of the Contract.

2. School unlawfully offered Contract, which they shouldn't sign, because they weren't authorised to extend my RP.

I asked them for 7000 Rmb (or budget return ticket to EU), but since they forced me to dial Gov., I added another demand: 'I worked 9 days in Feb, and I'm working 10 days in July, however I didn't (won't) receive pay for that. I'll just get holiday's pay (5000 Rmb) for each holiday month. 

They shortened me for approximately 14000 Rmb. 

The other thing is: 'last Contract should expire in the end of August, 2015. However for some strange reason, PSB gave me RP only till July 1st, 2015. We renewed Contract before that with expiration on July 1st, 2016.

School cut me off for 10000 Rmb (2 x 5000 Rmb holiday salaries), because 2 Contracts won't last 24 months, but only 22.

SAFEA officer talked to Principal last week, but everything looks 'cool&dandy' at the School. I'll know more on Monday, when I'll speak with Gov. again.

If I can respect the Contract, School can't BS me around!

Walk away AFTER I'll get my monies....? It's too early to tell that, buTT.....it will be interesting. I'll update!

My boss came to China a while back and I took him to this market to buy random gifts and sh** to take back home. I wad parched so stopped in this little shop to get a coke. This lady about 25 or so either was having a super bad day or REALLY hates foreigners because she was glaring at me and i just walked in. She hated me!

Anyways. I put the coke on the counter and she said 5 kuai. It seemed high but near a train station or parks they sometimes charge more. I gave her a 10 and just as i gave it a chinese guy came in and bought a coke. So the guy doesnt wait of course and throws a 5 to them but doesnt leave. He wants change! Hahaha its not 5 its 3!

So now im laughing but i hate dicks so ill fight over 2 kuai. I have time. So now the lady is pausing and doesnt wanna give him his change as it will be obvious to me. Im standing there with a huge grin.

After it got akward she gave me a dirty look and passed him 2 kuai. He left. I didnt. I stood there smiling. She said "what? "

I said in chinese " my change? You told me 5 but he paid 3, why? Are you trying to scam foreigners?"

She didnt get embaressed or say sorry like i assumed. She did that B**** face pfft. And said " because i said so". Totally defiant.

My boss is standing there confused as hell BTW.

So i was pissed. I said in Chinese. " Fu@# your mothers Pu@@j# you B****"

She lost her god damned mind and picked up a stool and threw it at me! It was heavy and hit the floor next to me. Shes cursing up a.storm. I understand half. She picks up another chair as i stand there laughing while her husband litterally hides behind her. And i said " if you hit me with that, i wont hit you, but i will really hurt your husband. Bad. "

Now a crowd had gathered and knew what was coming so they took the chair. I dropped 1 yuan on the ground and took another coke and walked away laughing.

So short answer is no, i wont just walk away.

How to suggest 'AoD'? We need one here-oo, or......'AoN' 

'Is Mike still on the bike?'

''What about Dong? Is he really that dong? Sorry, I meant 'long'.

English always mess with moi.

My respond for poor drivers or vendors , when I know they scam me, I argue with them to teach them a lesson, I get my money back then return it to them as a tip. I know they are poor and they keep the whole day working for just 3 or four kuais profit. BUT for cheap bosses (tou hao) who rip me off, I fight for each mao. It's like any other businessmen , you should play it fool to rip others off , so you need to play fool  to return to get your money back.