Anyone have any good tips on getting a proof of a no-show for travel insurance purposes?

Long story short, I had an itinerary involving two completely separate PNRs. One intercontinental leg taking me from JFK to CDG and an AF domestic leg taking me from CDG to LYS. Due to a 6 hour weather delay at JFK, I missed the flight. I believe this falls under the travel insurance coverage that many credit cards provide.

After some back and forth with the claims processing, the last thing i need is proof from AF that I was a no-show to my CDG-LYS leg. I tried leaving a message on AF's web site -- promising a response in 7 to 30 days. (Yes, it has now been 30 days.) I tried calling AF's domestic phone number and they said "we don't issue such documents, try filing a case online."

Any other ideas for obtaining this proof? Can I perhaps call a different skyteam partner who has access to the same ticket records. I can speak French and could also call AF in France. A couple hundred dollars is at stake, so I'm willing to jump through a few hoops here.

Thanks in advance!