Bought a shirt but seller did not disclose the bottom button was missing, do I have a case for return?

I bought a Saint Laurent shirt for $250 from a grailed seller. It arrived and I noticed that the bottom button is missing. He did not mention this in the listing, as I would not have bought the shirt if I had known, but the pictures show the shirt with the bottom button not buttoned. I assumed this meant the button was being covered by the other part of the shirt, and didn't ask for clarification because I thought it's something the seller would have disclosed. Now, I am trying to request a refund but the seller is slow at responding and is offering a $25 refund, which is not enough imo. I believe the shirt is not as described, so do I have a case with Paypal? I'm trying to settle it with the seller as for now, but I just wanted to make sure I have a back up plan.

Here's the listing: https://www.grailed.com/listings/3874617-Saint-Laurent-Paris-Polka-Dot-Crepe-Silk-Shirt

As you can see, the button is not visible, but the description has no mention of the button and it is not at all obvious the button is actually detatched