For anyone else in health insurance hell:
It happened *again*. After two years of polite phone calls every 2-3 months to my doctor and health insurance, the thing that got me unstuck was writing a polite email to the various CEOs documenting the delays, citing the state law requiring insurers to pay within 30 days, and asking for a written explanation as to why, 695 days later, they hadn't paid. Actual emails and phone calls from competent human beings within a week!
https://aphyr.com/posts/368-how-to-replace-your-cpap-in-only-666-days