If the practice is still remiss after you talk with the DO, or if you get a sense that the behaviors come from tone at the top, I would file a notice to your insurance company of the clinic's unethical practice to remove the clinic entirely from the insurer's approved providers. I might also contact a few of the other major insurance providers with copies of my records and correspondence with my insurance company. Insurers want to minimize coverage of services by disreputable service providers. Speaking as someone with experience in healthcare, insurers take this very seriously. You'd potentially be doing many families a favour, as I'm sure the share of insured clients out of all clients is high.

What is to give light must endure burning.