I'd never heard of Fullfitall, so I checked out their website.
Fufitall swimwear also does not give an address on their website, only an email in the contact details. This is their "bio".
About Us
FullFitAll is an international B2C fast fashion e-commerce platform. The team mainly focuses on women's wear, but it also offers men's apparel, children's clothes, accessories, shoes, bags and other fashion items. FullFitAll mainly targets Europe, America, Australia, and the Middle East along with other consumer markets. The brand was founded in October 2010, and since then it has upheld the philosophy that "everyone can enjoy the beauty of fashion." Its business covers more than 220 countries and regions around the world.
I suspect another Chinese company. Their returns policy is not good and they only tell you the returns address after you order. Terrible!