We use the DKT 2010-SD phone in our office. Recently, we've noticed that calls are not transferred to the voice mail on my phone, they are transferred to another extention if they are not answered. The "Do Not Disturb" button on my phone is not selected or highlighted, but when I listen to the user options set on my phone, it tells me that "Do not disturb" is selected. When I try to change the option, which would be option 1, that option is not offered. Is there a trick to changing the "Do Not Disturb User Option" that is not apparent?