AWS & payments integration expertise

Our existing backend is set up for an App yet to launch but firstly needs a Python code audit and rectification, particularly with the payments process. Looking for someone to advise on state of the code and then discuss path forward. Also need experience with payments integration and interaction with current Ionic App being managed by the App developer. Together you can make sure the selected payment gateway is quick and faultless! We currently are working with Google and Apple Pay (with errors) but can can move to a Stripe or other Payment Platform. We are using SES, SNS, Cognito, Lambda, DynamoDB, S3 and for notifications Firebase, with appropriate APIs. If you know AWS and payments platforms we would love to have you on board, initially to get the App launched but also if you are interested, for long term support and improvements. Thanks !