iPhone SE buttons and touchscreen not working

I've just received a new iPhone SE from my work. I went through the normal set up which all seemed to go fine. I let the phone lock and now I can't reopen it. THe phone recognises when I pick it up as the screen lights up. It also knows when I put my thumb on the home button as it unlocks and says to press the home button. However, if I press the home button, volume buttons, mute switch or lock button nothing happens. It means I also can't switch it off to restart it.