Ask her for a good picture of the defect. A close up, blurry picture is not acceptable.

As an aside, once an item is bought, the buyer can do what they like with it, including reselling it for more money. There's no law against that.

I'm just wondering what her game is? It's entirely possible she bought it to wear for an occasion rather than selling it. Wouldn't be the first time that has happened to clothes sellers! Some sellers track that persons FB page and often see the buyer wearing the very item which they claim is faulty or damaged.