I think if she complains to PayPal they will take it out of your account.
My husband sells on eBay and that happened to him. His item was sent to Germany and was in Customs for a while. He did get his money back after he proved that the item was received. It took a long time to resolve.
PayPal sides with the buyer and the seller has to prove that he did the right thing. Don't know how you do that without delivery confirmation or something like that.