[saltyESQ]

You should give the guy back his money. Bottom line is he didn't get what he paid for since you did not disclose complete info on the condition of the item and the limited info you did disclose was incomplete at best and misleading at worst. He doesn't need to take your discount on other equipment (nor would you do the same if you felt you had been burned once before). Even if you feel his gripes are unreasonable, you should give him back his money and be done with him. If you really feel your product is in great condition, you can explain that to the next buyer and disclose the issue so you don't have this problem again.