Cigna denying claims for covered services – advice for how to handle?

I’m going through IVF. I’m on a Cigna plan that has infertility coverage. While most of my claims for tests, procedures, etc. are getting approved, several claims have now been denied. The EOB lists the reason for denial as “Charges for fertility testing, treatment, artificial insemination or IVF are not covered under your plan.”

Except they are. I called Cigna twice to clarify my coverage, and my fertility clinic called multiple times to confirm that as well. The answer is always the same – my plan covers it, and there’s no lifetime maximum.

I have sent three denied claims for readjustment, and they came back denied again, and I talked to Cigna again and they sent them back as an escalation. Three more now got denied and I sent THOSE back for readjustment. Meanwhile some claims, from the same clinic and the same services, have been approved.

Any advice for dealing with this? Cigna customer success people have been invariably kind and helpful (and confused about why some claims are getting denied), but obviously they aren’t making the decisions on the actual claims, just sending them back into the machine.

I’m resident in MA but my employer is based in NY. Insurance is through the employer. The provider is in network.