Monthly Plan Subscription Payment solution for Asp.NET website using Stripe & PayPal

We are looking for an expert to integrate Stripe & PayPal in our existing Asp.net website. Main features required: 1. Monthly & Yearly Plan subscription 2. Add-on (Monthly linked with Plan) 3. Tokens (Add-on with One Time Payment) 4. Renew of plan every month 5. Add cards of customer and mark them primary or secondary. 6. We need to send coupon code and plan id and it should return the amount after applying discount with coupon details. So we can show customer that what discount they can get before charging their card… it is important because if we keep these calculation in system then their might be some difference due to any reason... 7. Option to change customer’s existing plan including add/Del add-ons and tokens. 8. Refund payment 9. Cancel subscription 10. Refund partial payment 11. List of invoices 12. Pending and upcoming invoices 13. Trigger our portal page methods on recurring payment (web hooks-- which eventually calls to our portal page methods). Our Portal is already built on Asp.net 4.5.2 & SQL Server 2012. We just need payment solution which can handle Monthly/Yearly subscriptions, renewals, discounts coupons, monthly/Yearly Add-on Sub/Unsub, Onetime payment Add-on. This project is divided in two phase. In 1st phase we required: 1. Integration using Stripe (We already have half cooked solution of .net but you can create your own) 2. Finalize Database structure in MS SQL for Monthly/Yearly plan subscription, Add-On & Token, Order and Transactions tables (Mostly done by other developer, you might need few modification to fit your solution in or you might change and rebuild from scratch) In 2nd Phase of this project we will integrate PayPal. Development Environment: We will provide you Windows Virtual Machine development environment setup with our asp.net system on IIS, Visual Studio 2015 & SQL Server 2012. We are open to suggestions regarding the approach to accomplish Payment Integration using PayPal & Stripe. GoodLuck