sounds like you have a problem with the email address entered on the listing form when you listed the item
if these are your first sales sounds like you have different ebay paypal email addresses and you have entered your ebay email on the listing form when should be your paypal emails
add both to paypal and the payment will show up if this is the case
room for 8 emails on your paypal profile
otherwise possible typo
click sell similar scroll down to the paypal section of the form and check it
if viable add to your paypal email profile
if not viable the buyer can reclaim payment using the cancel button and needs to use the send money tab in paypal to pay for goods and send to correct email address they need to enter item number etc on the payment or you can request money same way

Selling a mobile laptop or high risk item read Nigeria Scam
http://members.ebay.co.uk/ws/eBayISAPI.dll?ViewUserPage&userid=redalligator1