Cross-Platform E-Commerce App Development

I need a skilled app developer to create a cross-platform e-commerce app. The app should be user-friendly and feature-rich, with the following essential functionalities:

Payment gateway integration
User reviews and ratings
Product search and filters

Ideal skills and experience:
- Proven experience in developing cross-platform apps, particularly in the e-commerce sector.
- Strong understanding of payment gateway systems and user interface design.
- Ability to implement robust review systems and advanced search/filter functionalities.
- Proficiency in both front-end and back-end development.

Please provide samples of previous work and a detailed project timeline.