Clinic mislabeled me as in network, help dispute $1200 bill

Got 1200$ bill for preventative care (PCP visit + some routine vaccines) because my insurance was labeled as in network in the clinic's system. My insurance has individual and state plan, they are not contracted with the individual plan. Learned this with the bill and after speaking with my insurance.

I raised the issue with clinic manager + billing and they said they will modify their check in process, how my insurance is labeled in their system but will not adjust the bill. This process took ~ 1 month and I shared the issues in detail: website states my insurance is accepted, checkin person stated my insurance is accepted, and the clinic system labeled me as in network and the doctor I saw agreed to be my PCP (required for my insurance).

I was not given a good faith best estimate for private pay/out of network pay and billing informed me this happens a lot.

How can I further dispute the charges? Thank y'all!

submitted by /u/MainSea411