How do I report a website?

[allysa]

I recently bought some daily contact lenses from a website in East Asia. Unfortunately the contacts don't stick to my eyes. The first few days they worked perfectly, but after a week they began to fall out of my eyes or they would not even go in! I gave up wearing them and went back to glasses! I contacted the website asking for my money back or an exchange but they won't respond! I've waited for their response for almost 3 weeks but none were given. I want to report them, but I don't know how to go about it. I live in the United states and they are from Thailand or Vietnam. I also used paypal bill me later program to pay it if anyone wonders.
I did business with them before where I bought some contact lenses and they worked perfectly fine and the people were very responsive and polite.