I dropped off a usps priority envelope and 1st class mail with tracking a week ago in the blue mailbox a block away from post office,
they were expensive items sold through eBay.
I'm checking every day, no tracking
A few days before that I had 2 1st class envelopes returned because they weren't packages, I returned them to post office in packages and had them scanned, but they too didn't update any tracking info ( last tracking info was that they were delivered to me, when they came back before I re-sent them) and a case was opened on eBay against me for them already.
Bottom line USPS isn't reliable !