I can't stress this enough:

If you are having delivery issues, late mail, missorted mail, etc....

DO NOT stop at the postmaster for your town.

Talk to the postmaster, but ask them for the POOM's number. (Post Office Operations Manager).

For an extra bonus, write to your Congressman's office and let them know about your issues.

The USPS is being very badly run at the moment, and Congress has the authority and the responsibility to fix the issue. Ask them to enforce the 2-3 day delivery standard, and ask them to exercise their powers of oversight and remove the incompetent fools who are ruining the USPS so they can get a nice pension from a major mailer after their career at the postal service is finished. The USPS is YOUR service, not Pitney Bowes' service.