Why is my phone not shutting down? It has frozen

[AC Question]

I got a Vodafone smart ultra 6 which frozen on the password page, it won't let me shut it down or answer calls. It won't change the page nor shut down.
Please help.

 

[belodion]

Remove and replace the battery, or do a simulated battery pull: press and hold Power and Volume Down together for half a minute.