Defective Toy

Why do companies advertise and sell their toys for them only to be defective? One would think they know they are defective when they ship them off to companies to sell. Do they not get tested first? I am talking about what appeared to be a really neat toy for Trey......The Deep Sea JellyFish. So I told relatives about it. His aunt and uncle bought it for him. I was excited for him to have it. Well...I put it together today and it does not work. I finally get through to the company and they say to just get our money back. The toy was a popular item but it does not appear to work properly. Yea...figured that one out. Trey just does not have luck with toys lately