Welcome to China. The land of unethical business practice. The only recourse you have is to go to the Foreign Expert Bureau or the Police Service Board and file a formal complaint against the school. Or, you can hit every social media platform including WeChat, QQ, Youku, Weibo...etc.. and tell the story. You can also not do anything and take it as a lesson learned. China is China, it wont change for you and me.