Cross-Platform Reminder and Call App

I need a reminder app developed for both iOS and Android platforms. The app should include call reminders as a key feature.

Key Requirements:
- The app should send notifications for call reminders with sound alerts.
- User-friendly interface for setting and managing reminders.
- Integration of call reminders within the app.
- Notifications must be customizable.

Ideal Skills and Experience:
- Proficiency in mobile app development for both iOS and Android.
- Experience with notification systems.
- Strong UI/UX design skills.
- Familiarity with integrating call-related features in mobile apps.

Looking forward to your bids!