man, that's annoying. You definitely should refund him some of the money (and charge him just under the going rate.) Explain that it was a mistake that it was listed as 9999. How could you switched the price right before he bought it. It's not like you could have known that he was going to try to buy it at that exact moment. Really there is no reason for him to swear at you, he could have politely asked for the money, or politely explained what happened. It makes giving back the meat a WHOLE lot easier. (then tell all your PVP buddies on his level and in your clan to PVP him like crazy!)