1.If your supplier is a registered factory or company, you can go and meet local officials in person, seeking help from local government authorities in China. Normally you can contact following organs in China:
AIC(Administration for Industry &Commerce), Tax Bureau, Fair Trade Department with Ministry of Commerce and local Police Station etc.
2.If your supplier is not a registered factory or company, you can contact local Police Station if you know their Chinese name and ID in China.
No matter what kind of your suppliers is in China, you're required to report your case in details in Chinese to local officials if you need their help. Most of local officials know nothing about English and it's hard to catch the scammers with their created English names online. For example, in China, there are nearly 300,000 people sharing the same Chinese name 'Zhang Wei'. Normally local officials will help you out if you or your authorized Rep reports the case to them in person in Chinese, and the scammer can be heavily fined, jailed or forced to refund you as soon as possible. But sometimes the scammer is too crafty to be caught and also some local officials are badly corrupted and they are not willing to help you out sometimes. So Case-Report with enough proof is not 100% sure to get your money back esp when you did not sign any contract with your suppliers before.
If local officials do not help you out, you're suggested to make a small biz investigation to collect enough proof on their daily business activity, then consult local law firms and get ready to sue the bad supplier for their bad credit in China. By this way, you can get back your money; at least your supplier will suffer more from your case if you take above measures.For Alibaba members you can also contact Alibaba service team for help. For other scams, you can report your case to MOF for official assistance: www.mofcom.gov.cn
You can also book a Case-Report service from China STIN if you know nothing about Chinese.STIN service team has successfully got back millions of USD for their clients worldwide so far in China..