Help! Motorola V400 Keeps Shutting Off!

Hello.

Has anyone had problems with the Motorola V400 Camera Phone? I've had
the phone about 4 months now and when I go to end a call, using the
left side red key before I close the flip, it shuts the phone off.
Also, when the phone is off it'll just turn itself on.

Does anyone know about this kind of problem. Is it expensive to fix or
should I just look into a new phone?

Thanks!
Me