My mom just started selling some things on ebay as she cleans out her house, preparing to move. She had a coin that she put up advertised as a WWII Commemorative coin. She describes it in detail but does not exactly say what denomination it is. It sold for $18 - the guy gets the coin and emails her and says it is a 1/2 dollar & he thought it was the dollar based on her heading (which did not say dollar or half dollar just coin) so he would like my mother to refund some of the cost since the half dollar is going for about $16 based on one of his coin books and the dollar is going for $30 & he thought he was getting the dollar and he already has the half dollar. My mom is afraid of him giving her negative feedback so she isn't sure what to do. She had to spend extra money to ship the item since she didn't accurately weigh the coin so she is already 'losing' some money. What do you think? How should she reply to him?