$2000+ Ambulance Balance Billing in California, applied unreasonable in-network allowance. How to handle?

Hii. I recently had a fall earlier this month that resulted in a 911 call for an ambulance to the ER. My ambulance bill came and a claim was processed with my employer sponsored insurance (PPO BC Idaho). The bill was $2.7K in total, my insurance said that they applied in-network maximum allowance based on the CA pricing with their BC CA branch/partner as it was deemed medically necessary. This allowance is $615 and my insurance lets me do 80% as the in network. Therefore only $489 was paid for. The city/ambulance balanced bill me the rest and this was clearly showed on the claim, which is over $2k.

I am SO confused how this would make sense. I'm currently in CA and where the accident happened. Before calling 911 my partner called insurance to ask them about in-network ambulance and emergency room and said it was covered. They recommended 911 for the ambulance. Also, I got the best PPO plan with my employer. Also, there is no way any ambulance costs in this area is 615 bucks – they average around $2.5-2.7k (bay area). Now I'm stuck with a huge ambulance cost. I am going to appeal but I don't know that makes the most sense for my case. Any advice?

I was thinking of arguing in my appeal that this is out-of-network so the full 2.7K should be applied my that benefit of 60% covered. Which reduces my bill to around $1k. Is there any chance I can argue for an in-network coverage for the total ambulance bill in my appeal and win? Trying to just lower this bill…..