Stole items from my package and a plastic that was half open

I was recently sent a package of hair but my package was not completely sealed when I received it. I had 4 pieces of hair in the plastic but when I received it there was only 2 left. I contacted Courier guy and they took more than 4 days to respond to me and when I explained my situation they didn’t take me seriously. They gave me feedback after 2-3hrs saying they have investigated and my package was not tempered with. I fail to understand because I keep telling them that my package was not sealed, there’s no way an investigation was done that quick. I didn’t get the help that I needed from them at all, I doubt a thorough investigation was done. They keep saying it is not their fault but they are the ones handling the package. I’m failing to understand. This has been happening a lot lately and the courier guy has been so dismissive to the matter.