Comprehensive Billing PBX with Integrated Softphone

I'm looking for a seasoned developer to create a fully functional Billing PBX system. This system should come with an admin CRM, a User panel, and an in-built softphone.

Key Components:
- **Admin CRM:**
- The CRM should facilitate efficient management of billing and invoicing.
- It should also support customer account management.
- A robust reporting and analytics feature is essential for tracking system performance and customer usage patterns.

- **User Panel:**
- The User panel should provide access to call history and logs.
- Users should be able to view their account details and usage.
- A support ticket system should be incorporated for customer service inquiries.

- **Softphone:**
- The in-built softphone should only support audio calls.

Ideal candidates for this project should have extensive experience in developing PBX systems, creating customer relationship management tools, and integrating softphone functionalities. They should also have a proven track record in developing user-friendly interfaces.