It used to be simple.
The VHS player you just bought from Dixons doesn’t work, so you take it back to the shop and say “Oi, this doesn’t work”. They plug it into a TV, slot in a tape and either say “Oh, sorry” and give you a new one, or “Nope, it’s fine. Must be your TV or your tape”.
There were only so many parties that could be accountable for a product not working, and it was pretty easy to place the blame and get it sorted. It’s not so simple any more.