[mookie]

Here is one to look out for.

Seller send you an empty box instead of the item. They have proof of postage, even proof of delivery if you signed for it. Only way to prove you got an empty box is to get a police report (I was told that would cost £50 at least). An incident report (like for insurance claims) is not enough.

There seems to be no way to avoid this. Once the sender has posted the empty box with proof of postage, you are screwed. Maybe if it was sent via courier and you rejected the package on the doorstep, but even then...