Cross-Platform E-Commerce App Development

I'm looking for an experienced mobile app developer to create an e-commerce application for both iOS and Android platforms.

Key Requirements:
- User-friendly interface
- Secure payment gateway integration
- Comprehensive product catalog
- User reviews and ratings section

Ideal Skills and Experience:
- Proven experience in developing e-commerce apps
- Strong knowledge of payment integration
- Familiarity with both iOS and Android design guidelines
- Excellent UI/UX design skills
- Strong communication skills for regular updates

Please provide examples of previous work and a rough timeline for completion.