Are you trying to cancel a purchase?
This is a public member to member advice Board.
It is very unlikely that your seller is going to see your note.
Go to the listing.
Click on Contact Seller.
Explain your problem and ask for a Mutual Cancellation.
She may be grumpy (you have to click I accept TWICE to complete the purchase, hard to do accidentally) but probably will send you the request.
Agree to it immediately.
You will then be freed from the transaction.
Leave positive feedback for the seller. "My mistake. Thank you for the help." for example.