Gregory's Server@lrvick access to health care should not be limited by the type of phone you have. It seems implausible that office cannot communicate with patients outside of the app, for example they surely still have email.
“Note that an individual has the right under the Privacy Rule to request and have a covered health care provider communicate with him or her by alternative means or at alternative locations, if reasonable. See 45 C.F.R. § 164.522(b).”
@lrvick you can file a complaint at HHS Office for Civil Rights if you choose to go the route that this is a HIPAA violation. Here are more links that may be helpful:
https://www.hhs.gov/hipaa/index.html
https://www.hhs.gov/hipaa/for-professionals/faq/health-information-technology/index.html
https://www.hhs.gov/hipaa/for-individuals/guidance-materials-for-consumers/index.html