As others have said, clamping at the seatpost is best, although I'd be careful with a carbon fiber seatpost. That said, clamping to a smooth vertical pipe requires more clamping force and friction to hold in place. Holding a bike by a horizontal top tube near the balance point in v-clamp jaws requires much less clamping force, it will just sit in the bottom jaw, and need just a little clamp force on top to keep the bike in place. I STILL would not clamp carbon fiber there, and also not first choice for other materials, as some top tubes are awful thin these days; decades back I started to see Cannondale road racers where I could squeeze the top tube with my thumb and see it elastically deform, spring right back when released, but that's getting mighty thin.

But yes, brand-x tools frequently come with no instructions, or poor translation, and are not liable for "consequential damage", your only recourse is to return for refund, if able. So "caveat emptor", let the buyer beware.