Post Office Seizure?

ok, i ordered from a source and don't knowif the package got seized or not?

I went on usps.com
and tracked the package and it said that i recieved the package on fri
at 2:59 pm. but i never got a pink slip or got the pack. so i went to
the p.o. today and they said they didn't know wheere the pack was. They
sent me to their supervisor and she told me that she didn't know where
it was either. she said she didn't even have a record saying that it
was delivered or even attempted to be delivered. she said she was gonna call me tonight when the courier got back from all of his runs and she was gonna talk to him about it. She said she would for sure call me. But she never did.
How could a package just dissapear, unless the feds or someone took it
and didn't tell the post office, because they prolly wouldn't tell them
about it if they were tryin to set me up, would they? I'm really nervous
about this, and don't know what to do. am i being overly paranoid or am i doin the right thing.

please, someone gotta be able to help me out here. -thanks

it would be the postal inspectors to do it. maybe they left it at the door and someone walked away with it?

no, i live in a big apartment complex. they never leave the packages cuz they know that would happen. it's always waiting at the p.o. for me to pick up. am i being too paranoid about this or should i be nervous like i am?