After update my phone Samsung galaxy s7 doesn't turn on. What should I do?

Today I've got notification that there is update for my phone (Samsung galaxy s7). Everything was okay, until it turned off. It had to restart. I waited, now I see it loading, with Samsung logotipe. About 15 minutes passed. Also phone now is very hot and it doesn't cool down. What should I do? Should I wait? Or do something else? Please help!

That depends on your carrier. Some are pretty good, technically, and can reflash the update for you. Some are just stores that sell phones and accounts, and the associates know less about phones than you do.

If you can find your variant at XDA, see if someone has the current update file for your variant posted (or someone can post it for you) - then you can use Odin to flash it.

I assume that the phone was using the stock unrooted ROM. (If it was rooted or using a custom ROM, you'll have to reflash the stock ROM, and if you don't have everything backed up you've lost it.)

Get a iphone.