Flutter Mobile App Revamp

I need a skilled Flutter developer to enhance my existing mobile app on iOS and Android. The project includes:

UI/UX Improvements
- Refine navigation and menus
- Update color scheme and fonts
- Revamp forms and input fields

Bug Fixes
- Identify and resolve existing bugs

New Features
- Integrate calling functionality via Twilio api sdk
- Add 'Tap to Pay' feature using Stripe api sdk

Ideal Skills and Experience:
- Proficiency in Flutter development
- Experience with Twilio and Stripe integrations
- Strong UI/UX design skills
- Familiarity with bug tracking and fixing in mobile apps
- Experience in both iOS and Android app development

Please provide samples of previous work.