"I mailed USPO w/ Del. Conf. tracking # shows Delivered at correct address. Buyer makes a claim he never recieved item. I respond with sending him PO reciept, and tracking # explaining item Del. He still say's never recieved, he lives in a house in TX. He runs a PO search as I did gets a case # as I did PO tells us both item delivered date and time."

Sorry for your lose, Fred. That's gotta sting!

It's entirely possible that the package went somewhere else.
USPS Delivery Confirmation is a joke, a rip off, and totally worthless! ! !
If you are paying for Delivery Confirmation you are simply flushing money.

My mail carrier was running late one day and I arrived at my townhouse community mailbox at the same time as she did.
I was waiting patiently while she chucked the mail into the various compartments when I saw a padded envelope with a distinctive return address label being shoved into someone else's box.
I said: "Excuse me, I think that one goes in my box."
The mail carrier was immediately on the defensive. She refused to even look at the envelope again.
We argued for what seemed like five minutes, until I threatened to call the postmaster.
Finally she gave in and removed the padded envelope from the box and looked at it.
It had my name and address, AND a Delivery Confirmation bar-code sticker on it.

I don't know for sure, but I think all the Delivery Confirmation items are checked off as delivered before the carrier even leaves the post office. After that it's just a matter of luck if it ends up in the correct box.

If the value of the item you are mailing is more than you are willing to risk losing, then you need insurance and a signature on delivery. Delivery Confirmation is a scam!