I'd go to Facebook with a more or less polite comment about how you're having trouble getting a peace of mind insurance claim through. Don't light social media on fire yet, but once they see you taking it public it will be more of a priority for them. If they continue to ignore I'd continue to document your poor customer service factually on Facebook/twitter. And also call daily.
As someone that has had to escalate several issues with major companies (due to their lack of interest in helping me locally), once you start posting on Facebook, contacting the BBB, calling daily both locally and to corporate, in 3 different instances for us, these measures got results within a few days after dealing with it for weeks.
Keep escalating, don't give up. That is what they are hoping for...