iPhone 10 voice over black screen

[DA23Gam]

I've been practising using voice over on my iphone xs. I've messed up & now I have a totally black screen & the phone is unusable.
I don't know how to restart the phone to recover from this.
Help!

 

[DA23Gam]

Also, if I double tap the power button the phone speaks the time. If I hold the Power & up (+) button the flash light turns on & it talks about 'emergency services'. At one point I managed to restart the phone & it asked for the passcode. However, because the phone was in voice over I have to double tap each number in order to enter a number otherwise it simply reads aloud the number I pressed. So, double tapping each number until I've entered each digit the phone then tells me: 'incorrect passcode'. (it isn't!).

 

[DA23Gam]

Problem resolved by Apple support.