This happened to me over Christmas with a box of candy I had ordered from a company back east. It never arrived and the company said the tracking number said it was delivered. I told them no, then they contacted UPS who simply said their driver delivered it. I said No. Then UPS called me, I still said no I didn't get the package. Then the candy company sent out another box. It arrived in a couple days and then a day later the original box of candy arrived in a totally different location around my home then the UPS driver said he put it. Bottom line is that the candy store must have filed a claim, which tThe home owner that did receive the package brought it to my home and just put it on my porch somewhere. But it took them a few days to do so.
Now for the real crapper. My address, after 6 or 7 years or sucessful deliveries, is now labeled as "sign only". Which means I can no longer have packages dropped off at my home. Since I work every day, including the time UPS comes around, I'm never home to sign for anything. So now I have to reroute all my packages because one UPS driver delivered a $15 box of candy to the wrong house. And our local UPS office is over 50 min drive away. So its not convenient to just go pick it up either.
The sender is going to have to file a claim that you did not receive it. Then UPS should call you to confirm that you did not receive it. Then UPS will have to compensate the seller, and in turn he should send that money back to you.
Erin