Surprised that you are not complainng the insurance company about a medically necessary test bot being covered, rather complaing about the doctor for ordering the test.
But if the doctor did not order the test, and God forbid, it later turn out to be too late for a preventable or can-be-cured-at-early-stage disease, then you will sue the doctor.
Next time, just tell the "doctor" that you want the insurance company to make all your medical decisions so s/he can be off the hock. In the mean time, just pay it.