Comprehensive Radius Manager Development

I need a Radius Manager that encompasses user authentication and access control, billing and accounting, as well as network monitoring and reporting.

Key Requirements:
- Robust user authentication and access control: This should be capable of managing access for various user levels.
- Efficient billing and accounting system: The system should be able to keep track of user payments and generate invoices.
- Detailed network monitoring and reporting: This should provide real-time data on network usage and possible issues.

Platform Compatibility:
- The Radius Manager needs to be compatible and seamlessly integrate with Linux.

User Interface:
- The Radius Manager must feature a user-friendly Graphical User Interface (GUI).

Ideal Skills:
- Proficiency in Linux and Radius server configuration.
- Extensive experience in developing network management software.
- UI/UX design skills for creating a comprehensive GUI.
- Knowledge in implementing billing systems in software.