Explain the sizing, please?

I got to this product by searching for "Women's" sizes and then swimsuits. I am plus sized and ordered a size "22" of this suit. When it came, the packaging said "Size 22", but the suit itself is toddler sized, maybe a 3 or 4!I'll save the suit because I have a niece that is 2 and will likely fit into the suit next summer. However, there needs to be a clearer guide about how this is sized!