Buyer wants a partial refund

[ajaynepuddy]

I sold a coat as new without tags, it was bought in a sale online and I had just put it in my wardrobe and never worn it. The buyer has said it has obvious signs of ware and a stain, none of which I noticed. They say they want a partial refund due to high charges (I just went with what eBay suggested) but they don't want to return the coat as it has been dry cleaned. What would you do? I'm new to eBay so don't no the etiquette.