Urgent workplace issues, any help appreciated.

I am a teacher in Hunan. I have been working for a school here for 6 months so far. I have primarily taught 3rd and 4th grade students. No more than 4 classes a day and about 14 hours a week.

When I was originally trying to get the job, I negotiated a contract that said "No more than 4 classes a day for children aged 8 to 18." I signed that contract and under that pretense I took the job and flew over. When I arrived, they took all of the foreign teachers in the school and practically forced us to sign another contract, this contract being a version that I had never agreed upon. I signed it because I was new in China and easily pressured.

Two days into this new semester, they changed my schedule so that I'm teaching way more classes plus they are 1st and 2nd graders. This directly violates the original contract we agreed upon. I plan on going into a meeting with my liason this afternoon looking to compromise on something. I want them to either 1) drop some of the classes 2) pay me more or 3) send me back to the old schedule.

I'm afraid they are going to reference that new contract they forced us to sign, in which case I feel a little screwed. Regardless, I don't think they can spare me. They don't exactly have a lot of foreign applicants and one of the teachers up and left in the middle of the night last semester.

To buy my way out of the contract would cost $1600 and to leave outright without paying would forfeit any life I could potentially have in China. I don't want to leave, I just don't want my school jerking me around like this.

Any advice or help?