Hi.. If you plan to continue using ebay its best to open account and add the credit card.
Were you to open an account with the same information provided in the guest payment ( card, email address) the transaction should show in account's recent activity. Then click on PP resolution center and open an item not received dispute and escalate to a claim.
OR .. call PayPal with the info in your email from them and ask to open a claim. Toll free 1-888-221-1161
OR ..bypass PP and call the 800 # on reverse your card and ask for a chargeback. Have the transaction details available when placing the call.