The 'replacement' scam has been around a while now from primarily Chinese sellers.
FWIW there was probably no original item either.
Go to the credit card you really paid with. (Paypal is just a useful mediator) Phone the 1-800 customer service number. Ask the clerk about a chargeback. Have all your transaction details handy for her to process your refund.
You only have 45 days to start a Dispute through eBay or Paypal. Cards have longer deadlines, but they do have deadlines so act promptly.
If less than 60 days have passed you can leave Feedback for the crooked seller. The most effective FB is calm and factual. "Pd Nov 15 Not rec'd No refund No replacement' for example.
At the same time you will be asked to leave Detailed Seller Ratings. These are much more important than FB. The normal Rating is five stars. The lowest is ONE star. No stars is a free pass.
If the sellers Ratings drop below 4.3, his ability to list and sell on eBay are severely restricted, even ended.