If you place a bid on an item, and you end up winning it, you you should pay. Just because there are no other bidders, and you bion it, that doesn't mean you didnt' win it or you don't have to pay. One bid is enough to win an auctions sometimes. So when you place a bid, you're accepting the responsibility of a buyer who pays for the item.
In this case, contact the seller and ask them if you can purchase on of the two items you won. If they disagree, then ask them to send a cancel purchase form to you so the sale is cancelled, but seller does not always have to agree to this. Communicate with the seller and see what options they will give you.
