When USPS tracking says missent it means that the package was sent to the wrong post office that is local to your location.
The automatic scanning and sorting machines as the USPS sorting facility scanned it wrong and then sent it to be put on the wrong USPS truck.
When the USPS tracking says missent it means that the USPS is aware of it being at the wrong location and will then forward the package to the correct post office on the correct truck.
It will be hand sorted and loaded onto the proper and correct USPS delivery truck and should arrive at your house or address the expected delivery date.
However I've had a package that said that take a few extra days to get to me.
Things happen and even the USPS has a right to make mistakes as it happens to all of us.