Amazon used to employ the service of UPS a great delivery service. They switched to the USPS, generally OK. They then switched to AMZL, their own service. The latter is akin to putting a message in a bottle to send to Moscow and throwing it from the Verazzano Bridge hoping it will get there. Namely is just plain out does not work.
Thus for a company which seems to have its act together everywhere else why are the so grossly incompetent in doing their own deliveries? Simple answer; incompetent management. In my experience someone most likely got the job for reasons unconnected with competence. After-all who could not figure out delivery?
Well Amazon could. It is a shame that they are so grossly incompetent. Added to this no one really cares. Cracks in the wall like this often lead to a total collapse. Perhaps someone should notice. Doubt it however, egos always get in the way!