How come Calumet City IL. post office is so crooked?

I have had problems with this post office since i Moved here. It's very crooked I don't understand it. recently i had mail stolen from me the postman claimed he left the mail in my box turned out that was a lie he took it. Another time the same postman delivered a package that belonged to the people down stairs and I told him this does not belong to me so i gave it back to him his words were it's not yours ok I'm going to take it. I'm thinking he is going to take it back to the post office he took it alright home with him. Another time the postman who had my package from California in the truck just delivered my mail and didn't even leave my package I had to call the post office to make him come back and deliver it and when he brought it back he looked sad as if damn I could have stole that. It's crooked up there the people down stairs blamed me for taking their package which I gave back and the postman lied and said i kept it which was a bold face lie. I'm angry about that situation still why are these post office in Calumet City so Crooked?