The correct way to have dealt with this is that if you want to return something you "open a case" with eBay within 30 days. After that it is too late.
The seller sends you a label and you send the item back [beautifully packed of course]
The seller refunds. If no label arrives you "escalate" the case and eBay gets involved.
You seem to have done some "do-it-yourself" method outside eBay's rules.
If - after following the advice of @**peaseblossom** - you do not get a refund you may be able to contact your payment provider.
@mcp_max_vjmwsz