Hello, Jasmine,
That happening is one if my greatest fears. That is also why I buy insurance.
I did not look at your policies to see if you have covered it there, but please beware that there are people out there that claim nondelivery to get a refund. I am not sawing that is what happened, but something unusual did.
If you go to the USPS website, there is a toll free number to call to confirm the delivery etc, which may help. If the package is showing delivered, you did your part and that could end it for you. After you shipped it, it was out of your hands and you have confirmation of the delivery.
If you believe that the buyer did not receive it and want to either send it again, please at least get the insurance and or a signed confirmation of delivery. If making a refund to the buyer is a better option, you could do that.
I am just wondering why it took so long to find out that the package was not received....why so long to notify you? I find that most suspicious.
I wish you the best of luck!
Cocokate