Did you open an Item Not As Described Dispute in the Resolution Centre at the bottom of this page?
You have 30 days from delivery to do this.
The suggestion that you Contact the Seller is just that, a suggestion.
However, eBay does allow time for the Seller to respond. I believe this is 96 hours (4days).
The seller is required to send you a return postage, but if he is in another country, a Return Shipping Label is not possible.
If he doesn't send you return postage,you win the case and will be refunded.
Now.
If the four days have passed without response from the seller, and you are unable to ask eBay to step in and escalate to a Claim, you could go to Paypal and start a Not As Described dispute there.
You have 180 days from payment for this, BUT, PP insists that the buyer pay for the return of the unwanted item.
You are also covered by your credit card if you used a card to back your PP account, but that's usually the last route of appeal.