Personal opinion only: You look them square in the eye and say, politely but firmly, "I'm sorry, but that's not acceptable. I'll look into it and get back to you." You can be pleasant about it. Then go do your research (what I outlined above), gather your information/documentation, and go back and make your case.

I've had to do this many times with many doctors. As long as you remain positive, and with the attitude that you want to be proactive in your healthcare decisions, and help them help you, they'll usually listen and try to work with you. There are, of course, always exceptions. But this has been my own experience and best advice.

HTH & Best Wishes,

Doc