Customer ledger Management System for my cable tv business

I need a web-based customer management system to streamline my cable TV and broadband business operations. The system should be built on a technology stack compatible with shared hosting and SQL Server.

Key Requirements:

Customer Management:
- Add, edit, and delete customer details.

Transaction Recording:
- Record credit and debit transactions with a running balance.

Payment Tracking:
- Track due payments (paid/unpaid status with amount).
- Show a list of customers who haven’t paid in the last 3, 7, or 10 days (configurable) for reminder calls.

Reporting:
- Basic report of total credit, total received, and total pending (with details on collections, pending amounts, user details, and day-wise breakdown).

Data Handling:
- Import/export data in Excel format.

Ideal Skills and Experience:
- Proficiency in web development with SQL Server.
- Experience in building customer management systems.
- Strong understanding of transaction recording and reporting functionalities.
- Prior experience in data import/export.

Please provide samples of relevant previous work.