Have you opened a not as described dispute at the bottom of the page under Resolution Centre.
Escalate it after a full 3 days of opening the dispute.
The seller needs to send a pre paid label for the return.
A seller from China would be unable to do that and you may have to pay the return yourself
You could phone ebay and see what they say as sometimes they just refund straight away. Under Help and contact on your my ebay or Seller help on the seller hub and scroll down for contact details
Make sure it goes back tracked and that the tracking is in the dispute.
You have 30 days from the day of delivery to open a dispute in ebay
