How to cancel sale.

Hi i had a buyer purchase an item and now they say they wish to cancel as they didn't read the listing correctly. They paid with Paypal and I cannot find the cancel sale button. (Im guessing it's not there because it has been paid.) I did think of just issuing a refund from paypal but I would like to be able to get my fvf refund. If someone could give me some advice please. I'm heading out shortly and won't be back until after lunch. Thanx Smiley Happy