wait another 5 days then ask Ebay to step in if the seller doesn't respond.
The system is a little inflexible, that's certain.
The five day wait for a response is to allow honest sellers a chance to remedy the situation, and eBay really isn't taking sides on who is and is not responsible here.
Sigh.
So you can wait out the five days. Meanwhile eBay will be instructing the seller to send you a Return ShippingLabel. But the seller is in China , right? So he can't. (He couldn't from the USA or Russia or Brazil either, only from Canada).
When he doesn't respond, eBay will refund you.
Or try to escalate sooner. It might or might not work. Say in the Claim that the seller is Not A Registered User (NARU). That often helps.
If by some chance you get offered a replacement, say NO. It's not likely in these circumstances, but it's a fairly common scam out of Asia.