Hello @Kaye34,
You could try completing the listing and them immediately deactivating it. Remember that it will be live and bookable for the few minutes that it takes to deactivate it.
To permanently deactivate a published listing click on "Host" and then select "Listing". Then click on the listing to be removed and scroll to the end of the page. Click on the "Edit" button in the "Listing status" section and then on the "Permanently deactivate listing" link.
You could also contact Airbnb support. For information on ways to contact them type "contact airbnb" in the "Search the community" box on these forum pages where you posted your question. Scroll down a little in the list of suggestions that appears and click on the "Contact Airbnb: A Community Help Guide[UPDATED]" one. That lists phone numbers and ways to contact them via Twitter or Facebook.
Steve.