What is the source of the challenge? Is there a version in English? I am having very serious trouble trying to make sense of "your bank accounts can have multiple accounts for money".
I note that in your C# code a customer has an ID, a first name, and a last name. There is nothing about this in the challenge text, and since some people have one-part names, I have a three- part name, and my father had and my grand-daughter has four-part names, I should think that simply representing a name as a string without caring about subdivisions would be better. What I'm getting at is this: with a specification like that, how will you know when your code is correct?
