We are implementing the C# library from your code samples section.
So far everything is going well and we can interact with our contacts.
However, when using the Utility.SearchContactByEmail() method the ContactLists property does not contain any ContactList information for any search - always returns a count of 0 with no children. I have checked that contacts are assigned to lists in the ConstantContact account area; and they do.
Could anybody direct me where I might be going wrong?
The search by email API does not return the full contact. In order to get the full contact information you must perform the GetContactDetailsById method. You would want to pass the contact ID which you can get in the search by email method.
If you have any questions please let me know.