Insurance does not want to cover MRI, what do I do?

I have 50° Cobb angle scoliosis. My first spine doctor ordered an mri of my lumbar spine to see if I had any disk issues and also referred me to his colleague who specializes more in adult spinal deformities than he (mostly pediatric) does.

The second spine doctor was more concerned about the sustained clonus and hyperreflexia I showed during the neurological exam part of the appointment than the scoliosis. He ordered a full neuroaxis mri to check for neurological injury. Says he wants that figured out before we talk more about scoliosis surgery.

Now my insurance does not want to pay for the neuroaxis exam because they “already paid for one for my scoliosis.” They don’t seem to care that this is for a neurological issue, not scoliosis anymore.

It’s been a week long of me fighting with insurance, the doctor’s office, and the imaging center. The doctor’s PA said that he’s going to talk to the doctor to see if there’s anything we can do to get them to change their mind, but he thinks I might just have to pay out of pocket.

Anyone have any similar experiences/advice on what to do from here?