Getting UHC to pay out jaw surgeon Fees

My situation is pretty unique so bear with me: I had double jaw surgery recently and did everything my insurance benefits plan required (its stated its covered). I got prior authorization and network gap approval as no jaw surgeons are in-network with United Healthcare. As such surgeons require you to pay the fee upfront and your insurance should reimburse you after. Of course you know where this is heading, out of the 30k surgeon fees they paid 3k.

Ive tried several basic appeals (albeit not with documentation attached(oops)) and now it wont let me submit another. Im considering if going through the DOL is worth it or if I can hire some kind of lawyer?

Looking into lawyers because i have enough documentation to prove my insurance knew and agreed to pay for my surgery (e.g. all hospital fees approved), approved gap exception, etc. But failed to state that they wouldnt cover surgeon fees.

IF all else fails I work for a massive fortune 500 company and I may try emailing my CEO with the details, ive heard on self-funded plans this sometimes works. But its defintely a last resort for now.