@blaulcstar
Send a message to your buyer now, give him/her the USPS Tracking # and tell them the item has finally arrived in the US, should be delivered in a few days, and they can track its progress by checking the USPS site using the tracking number you provided.
Make sure you upload the tracking info/# if you haven't already into the transaction in your "Sold" folder.
Wait until the tracking shows confirmed delivery to the buyer, and Then CALL eBay, ask them to review your tracking info that shows the item was indeed delivered and see if they will reverse the refund.
I doubt they will, as I had a situation similar to this, and what eBay told me was that once a case is closed they can't re-open it. eBay considers their part in the process over and done with once a case is closed and won't do anything more to help you. But, you don't know unless you try.
If eBay won't help you, then I would message the buyer, say something to the effect that you noticed the item had been delivered and apologize for the delay in shipping which was out of your control. Then, advise them you will be sending an invoice via PayPal so they can now pay for the item they purchased and have received.
Up to the buyer of course, whether they decide to pay the invoice you send. If they are the decent/honest type they will. If not, I am afraid there's nothing much more you can do.
P.S. If you end up sending the buyer an invoice direct through PayPal DO NOT issue it associated with the original eBay transaction. Login to your PayPal account, click on "Send & Request" from the menu bar at the top of the screen, then select "Create Invoice."
Next, click on "Create" and fill in all the pertinent details. If you want to increase your chances of the buyer paying the invoice, you might want to only bill them for the item's purchase price and not ask them to pay for the shipping since delivery took so long.
If you decide to do that, be sure to mention to the buyer that's what you are going to do as a courtesy for their patience when you message them after you're able to see the package was delivered via USPS tracking.
If you're lucky, your buyer will see you're trying to make things right, and they'll pay the invoice you send. If not, as I said earlier there's not much else you can do except learn from the experience and move on.
HTH
