React Native iOS Build & In-App Purchase Fix

I'm facing an issue with my React Native application specific to the iOS build. The problem arises when trying to implement in-app purchases, which leads to a payment processing issue. This is preventing the successful packaging of my application.

Key Requirements:
- Identify and rectify the payment processing issue
- Fix the build failure during the packaging stage
- Review and optimize the custom logic implemented for in-app purchases

Ideal Skills and Experience:
- Proficient in React Native and iOS development
- Experienced in dealing with In-App Purchases
- Familiar with troubleshooting build issues in packaging
- Ability to analyze and improve custom logic in code
- Swift and effective problem solver