I do eBay to buy and to sell and I have never had a package that was handled by the United States Postal Service take longer than a week. If you had one take a whole month, it would be anecdotal and an exception so not illustrative of reality.
On the contrary, this was the second package from the same source, and I thought long and hard before ordering a second one. There won't be a third; I don't need the frustration.
The first was about three weeks, sent from ANDOVER, KS via the CHICAGO IL LOGISTICS CENTER where it languished for 12 days.
This one also sent from ANDOVER, KS via the CHICAGO IL LOGISTICS CENTER where it spent a week - then it came to within 40 miles of us (AUSTIN TX PACKAGE SORTING CENTER), then bounced back up to the DALLAS TX LOGISTICS CENTER for a few (business, not weekend) days, then showed up in our mailbox the following week.
The first arrived damaged, the second made it clean.
USPS has only one job: move material from point A to point B in a safe and timely fashion, and they suck at it.