Hi there
I can definitely help you with your requirement to process card-present transactions with C#.
I have worked in the card processing section of a major retailer, doing analysis of the ISO 8583 card present transactions flowing across their network.
I am also highly experienced in .NET, C# and SQL Server.
We would need to have a brief discussion for me to understand what specifically you need built, and how you plan to integrate it with your larger environment.
I would also need a simulator to build software against, or a very clear specification of the format of the data the card will contain and your back-end switch will expect.
Looking forward to hearing back from you!
Regards,
Joon