tvins.comは安全ですか？

I would classify this as a scam, bad customer experiense, and useless. They are a TV-shop, and like all of them, they sell crap for ultimately high price. For an example, they are selling currently a "H2O Vacuum", which "cleans even the dust and dirt you can't even see with your eyes". If you can't see it, it's not dirt/dust. That's b***s***. Never buy anything from the TV-shop. You're good to go with your normal vacuum. If it brokes down, buy a new one from the mall, not here. And any of those weight-losing stuff, such as "Vibratone", they are also just a scam. They use mens who have muscles already in their ads, saying that "Vibratone made this all" etc. Seriously, avoid these eeeevil TV-shops.