Communication breakdown? No. It's a straight out scam.
The point is to keep you hanging until the deadline for a Dispute passes.
Go to the Resolution Centre at the bottom of this page.
Open an Item Not Received dispute.
The first step is to contact the seller, which you have already done, so go to Step Two and escalate to a Claim.
If the seller cannot prove that you have received the item (which I suspect never existed) he will be told to refund you in full.
If he doesn't Paypal will and go after him for their money. He will not like that at all.
If you can't open a Dispute in either eBay or Paypal, go instead to the credit card you really paid with. (PP is just a useful mediator). Phone the 1-800 number on the back of the card and ask the customer service rep about a chargeback.