On the listing there is a link for Contact Seller.
Ask the seller for a Mutual Cancellation of the unwanted item.
If she sends the Request for a Mutual Cancellation agree immediately. Both of you will be released from the agreement.
You may find it helpful to explain your problem here:
https://translate.google.ca/
Write carefully in your first language, and use correct spelling and grammar.
Then translate your words into English.
Send the seller both explanations.