Senior Apple Developer for IAP Issues

We are seeking a senior Apple developer to conduct a quick review of our E-Reader application, which is currently experiencing issues with In-App Purchases (IAP). The primary problem is that the app fails to detect IAP products and encounters errors when attempting to retrieve the products list. Your expertise is essential to diagnose and resolve these issues effectively. The app was developed using Reactive Native + Expo.

We want you to handle these tasks:
Review the existing app code and configuration
Identify and fix issues preventing IAP products from being detected or fetched
Ensure full integration and proper communication with Apple’s IAP services
Verify that the complete purchase flow (fetch, purchase, restore, and database update) functions correctly
Prepare and successfully submit the app to the Apple App Store

The project will be considered complete when the entire IAP flow (fetch, purchase, restore, database update, etc.) works correctly while retaining all existing functionality, and the app is live on the Apple App Store.

Before completion, we expect proof that the IAP flow is fully functional, provided through screenshots, screen recordings, or TestFlight access for verification. After completion, please provide the updated project files along with clear documentation detailing all relevant changes made.