If you are a newbie and first time buyer on eBay, be ware that some sellers may trick you and won't deliver the item. Causing you to think the item has lost in the process and make you believe that the seller has posted your item and must have lost by the post office.
Be NOT afraid!
Contact the seller and keep all the email correspondences that you deal with and login to your My eBay area and submit the DISPUTE ticket.
eBay official will contact the seller and deal with it. I had mine case sorted out by the eBay officials.
WHAT YOU CAN DO TO HELP!
After you have sorted out the problem. Leave a NEGATIVE feedback about the seller. And keep the sellers honest!
If the sellers has low feedback, it helps to use the registered mail for the piece of mind. A little extra cost will help reduce headache.