I paid and trusted the mail service to deliver my package. I mean, that what they do to stay in business.
Actually, no, it isn't. The USPS is granted a monopoly on "mail". They needn't figure out where your package is in order to stay in business. This sort of thing is what keeps FedEx (where I work) thriving. UPS too.
FedEx and UPS are better, but they are not perfect either. You must pay extra for insurance with them too. Sucks, but it is what it is.
Sorry for your loss.