Just as well you couldn't find it. Tell your seller the dispute will be closed when you receive what you have paid for.  If they have sent a replacement with tracking then they can provide that tracking to ebay or Paypal, whichever resolution process you used, and the dispute will be closed. 

If you do close it now and the seller doesn't send anything then you cannot re-open the dispute and will have done your money.

If it is more than a couple of days since you opened the dispute and the seller has not provided valid tracking I would escalate to a claim if you haven't already done so.

If you get your money back and the item does eventually turn up you can always remake the payment.