Body con apron style mini NWT

I just purchased this and it’s too small!! I love this simple black apron style body con with back slit. Size 0- says fits xs/s. Just a little too snug for me. Very cute- purchased from azalea San Francisco boutique. New with tags, just received in the mail but it was final sale. Urban outfitters for exposure. This is a Herve Leger style dress, but not the actual designer as it for sure does not forgive or hug the body if it is too small!