Revenue codes for emergency room

Edit: my title isn’t great. Should be more like: insane cost for CT scan and ER visit. What can I do?

Hello! I went to an ER for abdominal pain and wanting to rule out appendicitis. I was taken into a room where they attempted an IV but were unable to get a vein, so they drew blood and ran a few tests. While the tests were running, I was put into a general waiting area with other patients. After nothing came up as abnormal, they decided to do a CT scan (without contrast because they couldn’t place an IV). After some time, I was discharged with no abnormal findings.

About a month later, I was diagnosed with gallstones that were causing the pain, but they didn’t seem to notice the stones on the scan.

ANYWHO, I was charged $14,671 for a CT scan abdomen and pelvis without contrast and $10,238 for level 4 emergency department care, for a grand total (including labs) of $27,649 billed to insurance (Anthem Blue Cross Blue Shield). I’m shocked at this cost for a few reasons. 1. they missed the gallstones 2. I wasn’t given a room and they charged $10k for sitting in a waiting room. A quick search shows average and fair cost for this service is about $700. Wtf can I do? I know this is like imaginary money to these organizations, but this is insane…..