My ex husband did the same thing. I contacted my attorney and she told me the best, and cheapest, way to go was to write him a letter advising him that he has 2 weeks to respond to your request and send it to him by certified mail. Don't be hostile or anything, just very matter of fact. If he lets the 2 weeks go by without an answer then you have two options. Either go to child support enforcement (if you are receiving child support) and ask them to inforce the court order. They have attorney's that will go to court for you and it doesn't cost you a thing. Basically they would add the premium for the health insurance to his support and then you would pay it. Or your second option would be to file a "motion to compel and/or enforce" with the court directly. I had to file one last year and it cost me $50.00. But what that does is, it will go in front of a judge and he will determine a court date for you to present your case. You can also file a "motion of contempt". It doesn't really do anything unless your claiming something REALLY huge, but it stays on record with the court and then if he ever does this or something like it again, it would give you stronger ground if you ever want to change the custody agreement. Make sure you keep copies of EVERYTHING!!!! No matter how minor it may seem....keep a copy and take it to court with you!!!! I can not stress that enough!! Also another thing you can do is contact the insurance company directly. At first they may tell you they can't talk to you but let them know that this is court ordered and that you will provide them a copy of that order...then they usually will talk to you. Hope this helps!!!
I'm a divorced and remarried (to the man of my dreams) mom of 2 beautiful children ages 5 and 9.