I am currently in the insurance business. Absolutely contact Ins commissioner. You must do (and should document) all steps with Insurance company. It helps to copy the insurance commisioner (acrually put the cc at the bottom of your letters to the Ins Company. That will get them moving. State in your letters what you want and when you expect a reply. (part of the necessary documentation. The Commissioner will open an investigation nad the ins company has ten days to respond to him/her. It is also free whereas an attorney would not be. You can always use an attorney later if necessary, but I doubt that will be needed.
The insurance commisioner has the power to forbid an insurance company from operating in your state. That is what gets them moving right away.
Keep at it.
regards,
Chris