You need to first close that transaction as the item did sell, and eBay charge their seller fee the second an item sells, and not when the buyer pays you.
Has the buyer of the auction sale, definitely pulled out and told you they don't want the item? Then a full 48 hours after the non payment , you need to open a case for unpaid item from the Resolution Centre, link at foot of most pages. Close the case on day 5 , your seller fee is refunded, the buyer gets a non payment strike, they are only allowed one, and only then should you relist the item., or offer as a second chance offer.
If you want this second highest bidder to pay the price achieved, relist the item for that auction price, the buyer bids, when they are able to pay, and you can go right of the item to More Actions >> Sell to highest bidder. Listing it as Buy it Now price is fine, but would not stop anyone else buying it, if they were quick.
