The most common reason for missing country or state data is that your billing system  does not contain country data for customers.

The customers country can be seen in their customer details under location:

If you want to take full advantage of ChartMogul's Maps feature you need to add the country and state data to the customers in your billing system.

If this is not available in your billing system for any reason, you can add it manually via the user interface by clicking on "UPDATE CUSTOMER DETAILS" then entering the information.

Another option to add this data would be to use the Import API.