I had a very similar experience. Except unlike you I wasn't aware of that requirement at the time, and ended up paying all of it. I did complain to the insuranc

I had a very similar experience. Except unlike you I wasn't aware of that requirement at the time, and ended up paying all of it. I did complain to the insurance company that the amount I owed didn't seem right, and they told me it was my fault for using an out of network ambulance.