Most if not all packages nowadays around the world arrive sealed. Be it the actual product or the packaging it was shipped in. Although the sealing can be reproduced by anyone, it’s usually sealed by some sort of a machine that most people probably don’t have access to.

So if you film yourself opening a sealed product, it will be a pretty decent proof that you indeed did get the wrong item, instead of the seller having to trust your words with no actual evidence behind them.