St Petersburg FL and Sarasota FL.

Except for high humidity we have no weather related transportation delays.

This is also the first time in 40 years I've seen Sarasota as the drop for St Petersburg. Usually it's Tampa.

Needless to say, I'm pissed about this one.

Bills mailed arrived several weeks late, this is in Florida also. I have relied on the Post Office for many, many years so it has been a surprise.

that go through the post office here in NC.

I don't know what the story is. We've had excellent postal service for the almost 17 years we've lived here up until the last year.
And I've had several problems with delays--or things that should have been delivered in 3 days taking a week--that are trackable.

Good luck. I hope your certified letter gets moving again.

I bought something off eBay two years ago that I didn’t like when it arrived, and got permission from the seller (in a small town in Georgia) to return it for a refund.
He only asked that I send it USPS with a tracking number.

I tracked it all the way to Atlanta, when the tracking stopped. It seemed to have vanished.
I inquired with the postal service for several weeks, and they kept responding “Tracking shows it is enroute”.

The merchant went ahead and refunded my money, but I don’t know if he ever got the item back.

I'm also in Florida (Space Coast) and the folks at my local one (right across the street, by the way) are always helpful. Pick a less busy time of day, show them your info, and see what they can find for you.

Do that immediately. No one is going to know what is going on until you officially complain (fill out a form at the PO). Sorta like a missing person, you know? The cops don't go looking for someone who's not missing. Talking to your local carrier is not enough.