After you make a purchase using Buy It Now on eBay, the only way to cancel that purchase is to contact the seller and make a formal written request. If you are the seller of an item and want to remove the Buy It Now option from one of your items, edit your listing to change your item from the fixed-price format to the auction format. You can also delete a Buy It Now listing entirely by ending it early.
Request Cancellation of a Purchase You Made
Visit the eBay website, log in to your account, click the My eBay button along the top of the screen and select Purchase History.
Select the listing associated with the Buy It Now item you purchased.
Copy down both the seller's eBay ID and the item number for the item you purchased. In the provided example image, the item number is the top number and the eBay ID is located beneath it.
Visit the eBay Advanced Search page, enter the seller ID and item number in the provided fields and click Search. Follow the prompts to send a message to the seller. In the message, outline your situation as best you can, explaining why you want to cancel the purchase. Keep in mind that sellers are not obligated to cancel the purchase.
If the seller does not respond or refuses to cancel the purchase, you can also refuse to pay for the item. If you go this route, however, an Unpaid Item warning may be attached to your eBay account. EBay may limit or suspend your account if too many of these warnings are recorded against it. Read eBay's Unpaid Item Policy for more information.
Change a Buy It Now Listing to an Auction
Sign in to your account on the eBay website, click the My eBay button at the top of the screen and select Selling on the drop-down menu.
Click the Active link in the Sell section, check the box next to the Buy It Now listing you want to change to an auction and then click the Send to Online Auction button.
Click the Edit button, select Format and then verify the details of your modified listing.
Cancel a Sale or Delete a Listing
If you're the seller of an item that has already been sold using Buy It Now, you have up to 30 days to cancel the transaction. Click the My eBay button at the top of any page and select Sold. Click the More Actions drop-down menu located next to the item and select Cancel This Order.
If your listing has not yet finished, end it early to prevent someone using the Buy It Now feature. Click the My eBay button and select Selling. Click the More Actions drop-down menu next to the item and select End My Listing Early.
Depending on the length of time remaining in the listing and whether any bids have been made for the item, eBay may charge you a fee to end the listing early.