Spring Boot Developer Needed

I'm in need of a Spring Boot developer with experience in implementing payment module including wallet in order to add it to existing application

Key Requirements:
- implementing payment module including payment and invoices services (for now we can use mock and it should be prepared to integrate it with third party later)
- implementing wallet with the following feature:
- as user consume, and view history of wallet balance.
- as user I can use gift cards to charge my wallet
- as admin I can add refund to the user
- as as system I can hold some amount of user balance until his service done in order to consume it.


Key notes:
- the developer should apply the best practices and clean code (from architecture perspective, security perspective ... etc)
- I need to apply on hold payment, which it means I'll get user approval to hold the amount and wait for his service to be done successfully then the system can consume the amount from payment, wallet ...etc "note that if the payment fail the wallet should be updated with minus amount"
- ensure the implementation provides data integrity


Experience Required:
- Proven experience with Spring Boot is a must.