[mothered]

Just to know and perfect my methods, I should have told them that inside the shipping box there were neither the headphones nor their packaging? (empty box, the box and Its contents was missing) or I should have told them that the wired charging case was missing along the headphones inside the packaging of the headphones itself. (The Missing Item Manufacturer Error).

It doesn't matter, whatever you prefer.

If the manufacturer can make an error solely with the headphones, then the same can be said with the entire contents.