Per the User Guide:
If something isn’t working right, try restarting iPhone, force quitting an app, or
Restart iPhone: Press and hold the On/Off Sleep/Wake button until the red slider
appears. Slide your finger across the slider to turn off iPhone. To turn iPhone back on,
press and hold the On/Off Sleep/Wake button until the Apple logo appears.
If you can’t turn off iPhone or if the problem continues, you may need to reset iPhone.
A reset should be done only if turning iPhone off and on doesn’t resolve the problem.
Force quit an app: Press and hold the On/Off Sleep/Wake button for a few seconds
until a red slider appears, then press and hold the Home button until the app quits.
You can also remove an app from the recents list to force it to quit. See “Opening and
Switching Apps” on page 29.
Reset iPhone: Press and hold the On/Off Sleep/Wake button and the Home button at
the same time for at least ten seconds, until the Apple logo appears.
I have owned Apple gear since early 1984, and have not yet met a problem not easily solved. The essential thing is to keep breathing, not panic, and not rant.
Thanks for your reply, done all of those above and it still crashed unexpectedly, we have always owned Apple everything since about 2000 and never had a problem hence why I did not worry about buying a brand new one but this is getting silly, luckily I have got my OH who is a wizz with Apple so always sorts it out until it crashed next time!
thanks we know this is a very rare problem and have now checked the box, the IMEI number on the phone does not match that of the box that was sold to us as brand new.
Does Apple keep a log of all IMEI number phones that have been faulty and need replacing?
I am now trying to return this phone as faulty to the seller who is not wanting to take it back