Comprehensive Invoicing Software Development

I need a custom invoicing and billing software with the following features:

Primary Function: Invoicing and Billing

- Automated reminders
- Customizable invoice templates
- Online payment integration
- Old pending payment notification alerts via WhatsApp
- Live gold, diamond, and silver price updates on desktop
- Notes feature on the dashboard
- Sales and payment methods combined in a single voucher
- Tally or Busy-like functionalities

User Access Levels: Administrator, Accountant

Ideal Skills:
- Experience in developing invoicing software
- Strong understanding of financial software functionalities
- Proficiency in integrating online payment systems
- Familiarity with real-time data update features (like live commodity prices)
- Ability to implement customizable dashboards and automated notifications
- Background in creating multi-user access levels in software

Please provide examples of similar work done.