If the item shows it was delivered to the same zip code as the buyer's zip code, there is technically nothing you HAVE to do. Both eBay and Paypal will close an opened case in your favor.
What you feel your moral obligation is is another thing altogether. That having been said. What I would do is give a call to the buyer's post office and ask for a supervisor. I'm not certain you are aware that carrier's scanner units now have GPS tracking on them. The supervisor can look up exactly where the carrier scanned the item as delivered. If the item was scanned across town (happened to me once) and your item is easily replaceable, you may wish to help the buyer out. If the buyer opens an INR case, you simply answer with tracking and then call eBay CS and they will IMMEDIATELY close the case in your favor.
A few months back I had a buyer contact me and say that he hadn't received his item. He said he was traveling in the orient and that I should just "handle it". I contacted his local PO and they said that GPS tracking showed the item was marked as delivered in front of the address I was given. I contacted the buyer and let him know this and his attitude was still that it was my problem and not his. When I asked him to check with the occupants of the home and ask them to check with neighbors, he opened a INR case against me. I uploaded tracking and then followed through with a phone call to eBay and I had it closed within 5 minutes.
I thought that was the end of it until I got a chargeback through Paypal. This time he didn't use INR, instead he used a "code 85" when I looked that up it said that the buyer was due a refund and never given it. Had he used INR again, I would have won immediately.... AGAIN. I uploaded all the information I had available including the fact that he had already lost a case through eBay AND that GPS tracking showed the item scanned as delivered at his delivery address. About a week later Paypal released the funds and removed the case from my account. There was a note that it was still officially pending for 75 days, but in essence, I won the case.
Had he been more cooperative I may have been a bit more receptive to replacing the order. Given his unwillingness to even look for the package and the fact that GPS said the item was scanned in front of the delivery address, I felt my job was done.
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I'm not a lawyer, I don't even play one on TV
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