Greetings Material Girl, as Sellers we ALL have your dilemma. I had 2 buyers who both said their package was NOT delivered. I always have delivery confirmation on my items. 1 went to Paypal & 1 did not. On both I told them to ask the postman who delivered the item to ask where the postman put it. 1 never got back to me & 1 said it was never delivered. I called the postmaster of the city and asked him to ask the postman what was done with the item. The postmaster got back to me and gave me the info that the item was left on the porch at the request of the buyer. Not the end of the story. I gave all this info to Paypal - name of the postmaster & Phone# and Paypal ruled in MY favor!! the buyer was so MAD she returned the item postage due!! I refused it, afraid to open it. But in the end she paid for item + shipping. International buyers you have to be aware there are NO confirmed address but I have won a dispute with Paypal there also.
Because WE are not a business like Amazon with write off in non delivery or damage, we have to accept risk as part of selling. It can never be eliminated, there are wackos everywhere. Most buyers are fantastic people, think if you had a Bricks & Mortar Store.