UHC denied $25k claim as “unproven,” doctor won’t respond

My doctor recommended an outpatient in office surgical procedure that he said is standard for treating my condition. He said UHC covers it, and I didn’t find any evidence saying otherwise.

Mid July I got the denial, stating that the procedure was unproven for my condition (code: PE). When I call UHC, which I have done multiple times, they either say it’s because the physician failed to obtain prior authorization or it’s because it’s unproven and they need my medical records. They won’t give me a clear answer. The hospital’s insurance experts stated that they checked ahead of time and did not need prior authorization, but UHC says that they did. However, the code used for the denial isn’t about prior authorization, so I’m really confused.

My doctors office won’t send in the medical records despite me asking repeatedly, but my understanding is also that if it’s a prior authorization issue that is provider error and they cannot bill me. I just can’t figure out if that is actually the problem since I keep getting different responses. I simply don’t know if this is an issue I need to worry about.