Hate to say it, but they may also have been stolen. We have had literally dozens of orders (not consoles, mainly phones) received with missing memory cards and/or chargers, etc. Phones are always there, but many accessories / add-ons missing.
This is with a supervisor standing there watching the orders being packed and signing off on them being complete. It has gotten to the point we were suspecting the Chinese customs people. There is also a middle party in most shipments from China, the shipping agent whose employees or contractors pick up the packages from the seller. Then the shipping agent is responsible to get them to the correct carrier. Unlike the US and I assume the UK, the express companies do not send their people for the pickups.
So there are many hands involved. We've never encountered entire shipments being stolen, just the little things inside.
One exception, We did ship 50 consoles to a buyer in Boston and he claimed he only get 46, that the package had been opened, etc. Never got to the bottom of that one, but other than than one I've never had a package "raided" for major units.