I agree, we have had experience of items being faulty and having to return them to shop, I have never known anything like it, what a fandango, they almost always try to put the blame on you, they just seem unable to accept they have sold faulty goods, if you don't have the receipt you might as well forget it and just buy a replacement of whatever is faulty, saves a lot of grief and hassle.
The worst place in my experience is the room in Leroy Merlin where you go to arrange delivery of items, they put the staff who hate their job the most in there just to make customers lives miserable, although Milar and Media Markt run them close for the worst customer service.