Hi,
I took a look at the VB.NET code example for the WhatsApp Gateway API. The code was all within my understanding, as I have great experience working with APIs through VB.NET and C#.
I have worked on MVC and Web Forms enterprise applications for several years.
My Windows 10 machine has Visual Studio 2017 on it. I could provide you a well-coded VB.NET desktop application that lets you to send/receive messages through the WhatsApp gateway.
Please let me know if you are interested in chatting more.
I can give you a small sample mock up application using the WhatsApp API just to demonstrate to see if it is what you are looking for.
Have a great day,
Anthony