iphone x completely blocked

If your iPX is frozen:

On an iPhone X, iPhone 8, or iPhone 8 Plus: Press and quickly release the Volume Up button. Press and quickly release the Volume Down button. Then, press and hold the Side button until you see the Apple logo.

Regards

Giulio

If your iPhone, iPad, or iPod touch won't turn on or is frozen - Apple Support

My iPhone X is locked automatically and I tried possible ways to unlock but unable to do so. It's dialing 999when I press and hold the start and volume up button. Or it's giving the panic alarm when I press and hold. It's a brand new phone and I am disappointed. Can someone help?