Payment Gateway Integration into Flutter App

As a business owner, I need the payment gateway integrated into my Flutter app. I bought the app script from CodeCanyon. The payment gateway I need is Dinger Payment Gateway, and I’m looking for experienced professionals with previous experience with payment gateways to apply who have experience and references to show. If you can’t work with ready made app, do not
text me.

I need your applications to include past work and quotes for the project so I can review it and make sure I have found the right professional for the job. I am expecting quoted prices for the job as well as an estimation for the timeline to complete the job.