How do I communicate with my parent's doctor?

I live out of state from my parents. When visiting some months ago I took my power of attorney and their living wills to their docs office. Also had them do the medical info authorization and had the office list me as primary contact for appointments etc. getting the doc to return calls is still impossible. I Have to leave threatening messages with his staff. I want mom and dad to change docs but they won't even discuss it. So for now this is the best I can do

If your parents have given written authority for you to view their health records, you can either telephone the doctors or email your questions.