You did right by coming here. Don't listen to the other comments.
They are probably friends of the people. When you offer items, there should be a comparison chart. There was another site I came across and didn't realize it till they pointed out to check the size chart. I appreciated it because it wasn't noticeable that the stuff was from another country.
I saw that site that you got the dress from. I saw that dress. There wasn't anywhere to indicate that it was being made from another country. Yes they should point out that the sizes should be size adjusted in thought when buying and give a note to compare to our size chart.
By the way,to the person talking about sizes of Chinese woman.
They can be chunky like us to. Average size for average American women are about 5'1 to 5'5 and our weight is not an average toothpick.