Start by contacting the seller, explaining the problem and asking for a Mutual Cancellation.
If she sends the request, and she is not obligated to do so, agree promptly and leave positive feedback. "Thank you for your help. Looking forward to buying again." for example.
You should also leave Five Stars for each of the Detailed Seller Ratings.
It may take a couple of hours for the listing to reappear, but the seller can leave you the new listing number. If you put that number in the Search box, it will show up for you before it becomes public.
