Denying a return

[smith1199]

I listed an item, and received a bid within the first 24 hours. 7 days later, with only 3-4 hours remaining on the auction, the buyer sends a message to tell me she was no longer interested in the item and didn't want to purchase it. I didn't see the message until after the auction ended, because it was sent after midnight, but I sent a message back advising her of Ebay policy regarding bids and the binding contract. The buyer didn't pay, until Ebay opened an unpaid item case against her.

So my question is this... can I prevent Ebay or PayPal from refunding her money, if she tries to send it back when I ship it? I fully expect this to happen, otherwise she wouldn't have waited for Ebay to step in to make her pay. I had no obligation to cancel the transaction, just because she changed her mind, and she shouldn't be allowed to return the item for a refund. However, Ebay or PayPal could automatically refund her money, which will not be fair to me and will only reward her for going against Ebay policy. She dodges an upaid item strike from Ebay for paying, but gets her money back anyway by returning the item. Anyone know how I can deny her refund, and prevent Ebay or PayPal from automatically refunding her if this happens? Just want to be prepared. Thanks!