Recommended order
Do not delete the App. If it still opens, create a complete backup in Profile → Data & Security. Note the App version, iOS version, time, and full message, then send a description with no private data.
Purchase and iCloud
Sign in with the Apple Account used for purchase and choose Restore Purchases. For Cloud, confirm an active subscription, explicit Cloud enablement, available iCloud Drive, and enough storage. Do not uninstall to force synchronization.
Public-channel warning
GitHub Issues is public. Never upload medical records, backups, photos, contact information, Apple Account details, payment data, or precise locations.