Oh, so the wage slave Prime couriers do carry delivery notices, like every other doorstep courier in existence, which means Amazon does not need to pester consignees with rapid-fire phone calls.
I'll block whatever I please, thanks, including callers spoofing allegedly "safe" numbers. I can just see the South Asian crooks getting hold of this and claiming the courier needs a "processing fee" prior to delivery.
Sometimes they have trouble locating the delivery address. Like the package I received today. I live in a large and quite confusing apartment complex with poorly marked buildings. If I had ignored this call, my package would have been returned to the warehouse. Luckily the third time the driver called I answered and got my package on time. Not everyone in the World is out to dupe you.