Your advice is spot on. We had a very similar experience with Blue Cross for many years. I'd swear they have an RNG that randomly denies claims 80% of the time

Your advice is spot on. We had a very similar experience with Blue Cross for many years. I'd swear they have an RNG that randomly denies claims 80% of the time. You just had to fight each one on the phone. The people on the phone only had the apparent authority to "send the claim through the system again". About a month later you'd find out what happened. If denied again, we would just repeat until we eventually got lucky with the RNG. They did eventually pay everything they should have, but we'd average about two hours on the phone per doctor visit.