I ordered a Halloween onesie from an etsy seller last week. The seller said that she could do onesies in sizes 0-24 and to specify the size needed. I sent in that I needed a 3-6 month onesie. When the package came in, it was a Carter's 3 month onesie, which is too small. The seller wants me to pay to ship it back for the correct size. I think Tey should since Carter's 3m = 0-3 months. What would you ladies do?