The United States Pilfering Service sucks. Would if kill you to hire GOOD employees that want to do a good job instead of the crooks you currently employ? Just curious.
If they are dead you should refuse to accept the shipment. Contact the shipper and have them replace the plants.
While the USPS certainly has too many issues to describe, I would like to mention that while most post offices are closed to the public on certain days, the actual processing of the mail continues non-stop, 24/7, reguardless of holidays. During those times when the union postal employees have off, the work is done by contractors and “temporary” staff. I only know this because I worked for the USPS for 6 months between highschool and college. I was one of those “temporary” workers. My supervisor told me that as long as I was in a different department every 6 months, I could keep working there indefinitely and still be considered “temporary”, but I decided I’d had more then enough by that point (it was hard work and my coworkers were creepy).
I do hope your plants survive. Rest assured that they will not likely be parked in a truck that whole time.