Someone clicked the Buy Now button, then sent me a message that "This was a mistake." I sent him a message"Do you wish to cancel the sale?" Yes, he did. So I cancelled and relisted the item.
I did notice the buyer is a Seller+ with zero feedback, 20 Buddy Points, and one listing running.
I do have a question. Am I stuck with the Final Value Fee? I've never had a request to cancel before.