Yes, you should definitely avoid the Jiangning and Nanjing NDI training institutes! They have done so many horrible things to their teachers. I had a friend that worked there for over two years and was on good terms with all the staff there. However, as soon as she told them she wouldn't sign another contract (but would still finish her current one) they cancelled her working visa and foreign expert's certificate without telling her. They kept her passport for "visa related purposes" as they said but in reality just wanted to get her in trouble with the government for staying illegally. Stay away from this training center!!