How have you offered a partial refund? If she agrees how are you going to pay it, as once a case is open, the money is frozen and it is a full refund or nothing, you cannot make a partial refund, unless you have used a completely different procedure.
Buyer is far more likely to escalate to ebay to get a full refund, you will then get a Defect, ebay will refund at your expense, they will probably not even have to return the item, AND you will not get the selling fee refunded.
