Data Deletion Troubleshooting for PHP/MySQL App

I need an expert in MySQL, PHP, and JavaScript to fix a critical issue in my software.

Problem: User data gets randomly deleted, particularly after data entry.

Key Requirements:
- Diagnose the root cause of the random data deletion.
- Fix the issue to ensure data integrity.
- Ideally, you should have experience with:
- MySQL database management
- PHP backend development
- JavaScript for any frontend interactions
- Troubleshooting data integrity issues

Please share your relevant experience and approach. Thank you!