I haven't had much reason in my personal injury practice to really delve deeply into HIPAA, but I suspect the answer lies within that healthcare privacy law. I believe you are correct in thinking that your billing information is protected just like a patient's medical condition and diagnoses.
I have three young kids and I know a good pediatrician is hard to find, so try to work around this rude person.
You may find this link helpful in reviewing HIPAA; there is also a link for how to file a complaint. http://www.hhs.gov/ocr/privacy/hipaa/understanding/consumers/index.html
Review the Notice of Privacy Practices (NOPP) provided by the health care provider. Patients who believe that health care providers violate the HIPAA privacy rule, can file a complaint with the health care provider's privacy officer. Also, patients may file a complaint with the HHS Office for Civil Rights. Information about how to file such complaints is contained in the NOPP.
The information provided is for general purposes only and does not establish an attorney/client relationship.