Here's a good eBay dilemma for you..

I sold a rather expensive item on eBay two weeks ago.  The buyer sent me an email three days after they received it saying this:

Hello, I received this today and I realized I bought the wrong size.  Would you happen to have the smaller one? 

I responded:

"Yes, I do, but it is not in the original box like the one you received is. . I can trade the larger one for the smaller one, if you are willing to send the large one back before Thursday. Please let me know. Thank you!"

She responds with this:

"Hello, Would you sell the small one for less the what I paid for the large one? It isn't going to be in the original box and I will have to mail the other back to you, I am sure that is going to costa bit."

Here's a little background on the situation. 

• The size of the item is marked in the title once and in the description twice.
• She has 3500+ feedback, most of it as a seller
• Lives about 300 miles from me
• Has the item she wants to return currently up for sale in her listings.
• Thought she was buying the smaller item for the price she bought the big one at but now wants a discount on the small one.

Should I…

• Offer to exchange the large for the small at no discount?
• Offer to exchange the large for the small at a discount?
• offer no refund or exchange
• Offer a refund for the item only
• Or something else.