Did you pay by Paypal?
If so, you are covered for 180 days from payment.
The PP Resolution Centre is at the top of your PP account page under Tools.
The first suggestion (not a demand, a suggestion) is that you contact the Seller.
Just ignore that and ask PP to step in and escalate to a Claim.
State in the Claim that the seller is suspended (Not A Registered User/ NARU).
PP still has his financial information, and if he cannot prove Delivery (not shipping, delivery) you will be refunded.
If you bought directly with your credit card, go to the 1-800 number on the back of your card and ask the clerk for a chargeback.
She will need dates, payment amounts, currency, and transaction numbers, so have those handy to help her process your refund.
The safest way to buy online is through a Paypal account backed by a credit card.
This gives you three layers of protection, eBay, PP and the card.