United States Post Office lost item, refund, assurance Nationwide

Back in July 2016, I had ordered some pills online. I was tracking my item online & got a notification that it had been delivered on a Monday. I went to my local post office to check my post office box to see if it was there. It was not there. I asked the woman who works at my post office is there package for me. That day and the next day on Tuesday she said that there is no package. What is worse than that is that she did not even try to go look for it. I called the company and see what is the problem. They confirmed that it was delivered on Monday. When I had told her that on Tuesday, she still said that there is no package. I called the post office's national number and complained about it. I told them everything that happened. They kept giving me a case # and had people returning my calls and investigating what is happening. The manager at the post office in my town lied and told them that the woman searched for my items when I asked her for it. The manager even called me and trying to tell me that her worker did try to look for it. I told her that it is a lie and there was witnesses there to confirm it. She said that that is besides the point, and I should call the company and explained what happened and see if they can give me another one. The people on the national number told me to do the same thing. I e-mailed the company who sent me the pills and told them what had happened. As they perfectly stated, they would not do that since it did not get lost on there end (which makes sense & what I understand). Someone who is over the national post office in my state even went to the local post office in my town and investigated. They said that they went & looked and send that the item was scanned. I kept telling them that I did not get it. When I called the person back who was over things like that in my state and to see what is going on, she told me since the item that I ordered did not have insurance on it, there is nothing that they can do about it. Even though it was there fault that my item got lost, they would not pay to replace it.