I'm afraid buying on eBay is not like buying at a store. You can't just change your mind and cancel the deal. Your bid is a contract to purchase. You fulfilled the contract by paying - as you are legally required to do.
It is unfortunate you no longer need the item, but the seller is under no obligation to cancel the transaction.
If you feel that you have a legitimate reason for not buying the item, you can contact the seller and explain your situation. The seller may agree to cancel the transaction.
As a buyer, you're obligated to complete the purchase by sending full payment to the seller. If you don't pay, the seller can open an unpaid item case, which could be recorded on your account.
From eBay Customer Support:
"If you feel that you have a valid reason for not paying, you should contact the seller and explain the situation. If you and the seller agree not to complete the transaction, you'll be released from your commitment to purchase the item.
Read our unpaid item policy to learn more about your obligation as a buyer.
http://pages.ebay.com/help/policies/unpaid-item.html
Note:
If the seller takes returns, you can send the item back once you receive it. The shipping cost is your responsibility - and you must get tracking to prove it gets back to the seller.
