[mothered]

I ordered an item, say with a weight of roughly 2kg, however the parcel label on the box clearly says that the contents of the box weigh 100g.
Could I not simply say I received an empty box with the contents missing?

It may work In your favor, however the weight on the label, doesn't always represent what was Initially recorded at the carrier's depot when the package first arrived.

Human error when generating labels does happen from time to time. I personally did It just last week.