Xperia XZ keeps turning off

[CLW]

I have a brand new Xperia XZ and it just keeps switching off, if it's left idle it goes off and if I turn it to stand by it won't come back on properly. I can get the phone to reboot by using the power and volume buttons, but not the power alone. The phone was fine the first day I got it but the day after it was doing this and still is today, I'm not sure if it is a problem with the device itself or something that has happened after the recent update.
It's also taking a lot of battery each time it goes off and sometimes the phone seems to be completely off but will still have a light on, and also made the noise to indicate the phone was turning off yesterday when the battery died, despite already behaving as I'd it were dead.

[Jake-SonyXperia]

That is great to hear, however, I agree with @YoGem you should still try to perform a software repair on a device to make sure the device continues to work as intended.

[Pete_from_Londo]

I'm on my third XZ in two weeks.  There Is a problem which Sony is denying.  Hate this phone.  Have spent 5 days setting, resetting and doing what the Store have told me to try.  Sony were useless.  Just stonewalled me.  Now the third one is turning off the store has said they MUST exchange it for another make which is what I want.  Samsung again for me. 

[Littleblueshark]

right now is 05:00 on the west coast and my xperia xz would not stop turn off. i tried the  removal of the SD card and oh boy it worked my phone stopped turnig off. but i lost some apps . 

[Veggiemunch]

Pete from London.. On my second XZ in two weeks so frustrated  have tried every single thing possible its a peice .