In theory, no.
But eBay isn't gonna send a tattooed guy named Big Phil to his house to change his mind.
If the seller does not ship within seven days (or four if he's told you he's not shipping) you can Report him to eBay. There is a Report button on eBay Messages.
If you paid, you have 45 days to open an Item Not Received Dispute. This is harder if he has also refunded you.
If he sends a Request for Mutual Cancellation, you can refuse and leave feedback.
You have up to 60 days to leave feedback. The most effective feedback is calm and factual. "Refused to complete sale. Prompt refund." would be one. (Or 'Refund req'd dispute' as appropriate.)
At the same time you will be asked to leave Detailed Seller Ratings. These are much much more important than feedback. A normal transaction gets Five stars. The lowest Rating is ONE Star. No stars is a Free Pass.
If a seller's DSRs drop below 4.3, his fees may rise, his position is Search may drop, his ability to list and sell may be restricted, the number and value of his listings may be restricted, or he may be booted off the site.
