Build a platform website and 2 apps

we have done ui ux of the apps and website we need developers to build the projects at a fixed price within 20 days

the apps are
user app for selling products in stock as crowdfunded
business app to register and send there ads to the platform

the website is to register the user and both business for

user to purchase the stock of our product we issue . and maintain its revenue
business app is for business to register and send advertisement to platform

note : the products sold are digital signage stock and our custom engineering products
the business app is to receive the content of business to advertise the digital signage

the user app must be connected with stripe and razorpay payments system
as the user install the app goes to payments in india to razor pay and rest of the world in stripe payments

please note the ui ux shall be given on point of contact