lab test booking app

I'm looking for a proficient app developer to build a mobile E-commerce app that caters primarily to service sales. The app should be designed for both iOS and Android platforms.

Key Requirements:
- The app should have a user-friendly interface, allowing easy navigation for purchasing services.
- Secure payment gateways integrated within the app.
- Functionality for service providers to list their services.
- Integrate geo-location services for users to find providers based on their location.
- Incorporate a chat feature to enable communication between users and service providers.
- Build a booking system allowing users to schedule services in advance.
- Enable push notifications to inform users about service updates, promotions, and news.

Ideal Skills and Experience:
- Proven experience in E-commerce app development.
- Expertise in cross-platform mobile app development.
- Prior work with service-oriented apps is a plus.

The app should include user authentication via phone number. The user interface should follow a colorful and vibrant design style.