Big bad HMO

So I had an appendectomy last week. I'd gone in to get a CT scan of my liver, but after 24 hours in the hospital, two reviews of the scan data and an ultrasound, I was diagnosed with appendicitis and admitted for surgery. All went well.

Now, I get a letter from Medical Mutual, my insurer. In it, they express disbelief at the medical necessity of the procedure, and of my hospitalization. They claim they won't pay for any of it.

Now, I really didn't know that an appendectomy was an elective surgery.

... All has been sorted out. Seems they didn't receive notice that I had appendicitis, and had just heard that I went to the hospital with abdominal pain and was discharged. How they missed all that went on in between, I don't know...