*The customer service reps have to answer a huge volume of cases and they really don't take time to read the email
*It's ingrained into the customer service reps to follow policy to a T. So if it was signed for, deny.
*They're using some sort of automated system that shows whether something was signed for. If 'yes', deny.There used to be useful links ("Where's My Stuff?") directly attached to your order for inquiring about status if things are late, etc, with just a click or two... this all kinda still exists but has been buried so far up into the user interface that there's no way it isn't intentional obfuscation to try to limit any kind of meaningful interaction between the customer and anyone alive within Amazon, with a further barrier between the front-line alive people who are clearly all offshored and anyone in the US.
When I thought there was nothing else to do, a friend told me: "The first thing you need to do in Amazon, is getting in touch with a real human". And he showed me how, which involved a complicated series of UI steps. Once I talked to a real person I got my money back in a week.
So, yes, I definitely agree. Amazon is making it increasingly difficult to talk to real humans. If I can't get into a phone call, or at least a chat, I don't bother anymore.
I blame their extreme position ahead of other emarketers. They have very little reason to be nice and helpful. People will throw money at them regardless.