I would try to keep calling. I would also try to find another way to call -- cell phones, text messages/email, etc -- until you can actually get in touch with someone. I would also consider calling a friend in a different department to go by mine to ask them to call me. It could be a problem with the phone system. Ultimately though, if I couldn't reach them and needed to call off, I would probably ask a friend or family member to go up there and tell them in person for me. If it isn't safe for me to drive, I shouldn't be on the roads.