I'm really sorry to hear you're having problems with your Note 4 shutting down on you. This is obviously frustrating especially when you're on the phone to someone.
Did you get the handset from us?
Have you called us to report the problem?
If you got it from us in March then it's still under the 2 year warranty. Please call us on 789 from a Virgin Mobile handset or 0345 6000 789 from any other phone. We'll be able to diagnose the fault and decide on the next steps.