The shipment was finally located last night (after Amazon refunded the order and I placed a new order - the US rep on the phone was not able to simply ship replacements for some reason) and is due to deliver today, along with my re-order.I have a shipment of about four orders that Amazon combined that is scheduled to be delivered today, but UPS tracking only shows that Amazon created a label on Sunday night with no other info available. UPS shows the same. Yet Amazon is absolutely certain that it will arrive before 8pm today.
The shipment is being shipped out of Amazon's facility in or around Tracy,CA, and these types of things happen more often at that facility than any other, at least in my experience.