Club Management System Development

I need a comprehensive member management system for a swim and tennis club. The system should work on web, iOS, and Android platforms.

Key functionalities include:
- Billing: Manage all financial transactions.
- Program Registration: Allow members to sign up for various programs.
- POS System: Handle purchases and sales within the club.

User roles should include:
- Members: Access to their profiles, billing, and program registration.
- Staff/Admins: Manage the entire system, oversee transactions, and handle registrations.
- Guests: Limited access for non-members.

Ideal skills and experience:
- Strong background in developing cross-platform applications.
- Experience with billing and POS system integration.
- Familiarity with user role management in applications.