The phone rings but I am unable to answer. I

if your unable to answer the phone, just hang up and wait for another incoming call or press the power button

If you are having problems turning off this unit, the best way is to make sure the a/c adapter is not plugged into the machine, then remove all the batteries from the unit, and leave everything like that for about fifteen minutes. Once that time has elapsed, then reverse the operation, by putting the batteries back into the uniti. Then if necessary, plug the ac adapter into the unit, and finally put the a/c adapter into the back of the unit.
Ghen try to use it.