Postal Locations

Is it not illegal for the post office worker to be giving my mail to people that do not live in my house hold. just because they have the same last names does not mean we are on friendly terms with them. we had a package given to a relative because the clerk felt is was to bulky and she did not want to deal with it . we are a very small town she is having a fit if our PO Box is not on every piece of mail, some thing will not mail if it has a PO box on it. She has sent some peoples bills back who then have had there service shut off for none payment She does not pay attention to the names on the mail as we get peoples mail that does not belong to us but has our po box.