Connection of the payment module to the self-written site

The site (kostrovstore.com) was written in 2014, at the moment there is no support. It is required to connect the payment module from Tinkov Bank. Include examples of work, estimated timelines and prices, and contact information in your responses.

Web framework: Microsoft ASP. NET4.0.30319
Web Server: IIS10.0
Operating System: Windows Server
JS framework: Knockout.js2.2.1
Programming language: С #