I'm wondering if volume matters. I had 5 lost packages in the month of July. And about 3 since then. I don't have much respect left for the post office. When I put in the complaints for July, their first response is that it could have been my customers wanting more than they paid for. Not True!! About a month after I filled out the complaints, I got a letter that basically said, Yes they are lost. Changing post offices hasn't helped. Although, I haven't lost 5 in one month. Knock on wood.
Since then, I do offer the option of insurance and require it on larger purchases. I still tend to replace the small orders if lost.
Carol