When you send an item back and tracking has shown delivery, the seller has 48 hours to refund you.
If they don't, you Must escalate the case, ask eBay to step in, and they force the refund.
If you do nothing and forget to escalate, the case will close through inactivity. You cannot open another case for this item with eBay.
Turn now to your payment provider for help with your refund.
@christiaandejong0