There are 3 ways on how to Close Open Return request on eBay:
1. Refund the Buyer
2. Don't accept the return
3. Report the buyer or
Of among the three, Refunding the buyer is the most easiest way to close return. However, if your accepted the return, it's good practice to wait the item to arrived before you will issue refund. This will help you protect yourself from poor buyer practices but time consuming somehow. Anyway, for items that don't require return you can issue refund anytime to close the return or case.
Don't accept return. This is true if the return didn't meets your return requirements, for example, returning an item not within your stated time frame, and not meeting item condition requirements. You can close the return request immediately.
Report the buyer. If the buyer, didn't return the item even if you already accepted the return and issued return label, after 5 days you can file a case again't the buyer. Go to Manage Return then, report the Buyer
Select reason as " your problem isn't listed here" and send this message to eBay as shown:
If you're avail, you may also call eBay support for fast resolution - they would gladly take down over 5 days returns that has been approved by you but no return tracking # from buyer.
Just open this link to reach out eBay Customer Support: https://ocsnext.ebay.com/ocs/home