Build me a mobile app

I want a Android Mobile App that 1) login user with Google/Facebook/Twitter Id, 2) First In-App Purchase Item is mandatory(Basic subscription/Profile entry Payment) 3) collect Personal Data(Profile) with provision to update,(about 25 data points will be provided, some selection data points, while others will be formatted data) and store in a server through secured connection in a central database, 4) Additional in-App purchase options (5 products renewable) using google play store. 5) Search for Personal Data of others based on 3 preset filters, 7 optional filters. 6) Provision for Storing optional filters. 7) All filter information will be stored in server. 8) One instance of App can have multiple Profiles with same email and mobile number. 9) Each profile addition is allowed only after in-app purchase (profile entry payment) 10) Admin Panel for entering Profile Validity period, Amount for each in-app purchase should be available 11) Admin Panel should have refund option for payment. 12) Admin should have option to approve / reject profiles with refund of payment. 13) Admin should have option to refund payment (without relating it to approval/rejection). 14) Mail should be triggered for any action in App for actions by users to admin(for approval/rejection/payment check), actions by admin to users(for action update) 15) Option for integrating WhatsApp Business 16) App should have Provision for Testimonials by users 17) Home page shall display selected Testimonials at random Technical : 1) App should be developed using Xamarin and C#. 2) Database structure will be given, additional fields/tables if required should be given as script by developer. 3) SSL for connection (end-to-end) must be used.