Buyer Opened Return Request, Demanded Exchange

[slocough]

I have a buyer that opened up a return request, which I promptly accepted. I acknowledge that I had shipped the wrong size of clothing. The day after I approved the return she sent an email stating that she is still expecting the correct size. Of course, I said sure as I didn't want to create an unhappy customer. I shipped out the correct size and she shipped out the incorrect size. Of course, I provided the shipping label.

I have at this point received the incorrect size and the buyer received the correct size.

I very politely request that the return request be cancelled as the buyer now has the correct size with no additional cost to her. She did not respond so I once again sent a kind request for cancellation of the return request. This time I got an email stating that there was no way that she could cancel the request but it was nothing personal. She just doesn't have time to deal with it.

Do I need to write this off or will ebay give me some type of protection? Anyone have any experiences like this. I just have no desire to have a customer give negative feedback as they hold all of the power.