Take those contracts to a lawyer (you'll probably need about 5k, but an initial consultation is free) and let him have a look, if any of those terms are illegal (in the past, they have proven to be so accordingly to previous posters), your contract be declared void and you'll be free to go and won't need to give them a single penny. Make sure that other affected teachers are made aware of this too and take action together.

Also, go to the Labour Bureau and Foreign Expert's Bureau and make official complaints, but get your lawyer to help you out with that.

Start looking for other jobs now. Many public universities (or schools) will be in need of new teachers for the next semester and you can apply directly, you don't need an shitty agent like Worlda to illegally farm you out to them either. Also, private companies don't like to try to f**k with public universities who can cause them some real trouble.

Be completely honest about your situation, when applying too. Universities are aware that there are some dodgy companies out there and can easily tell apart a bullshitting idiot from a honest victim. I presume that you fall into the latter category and will have nothing to fear.

Good luck.