Get and update a user by Username

So the APi doco is sparse on getting and setting a user by username. We have an issue where some of our usernames are all numbers and the API is treating them a UserID and not a user name. 

Getting a User

I can use this code to get a user in c#, but I am appending ?username=## to the url. So it seems like a hack

public dynamic GetTelligentUser(string username)
{
    ServicePointManager.Expect100Continue = false;
    ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

    var host = new ClientCredentialsRestHost(
        communitySettings.Username,
        communitySettings.Endpoint,
        communitySettings.OAuthClientId,
        communitySettings.OAuthSecret);

    var response = host.GetToDynamic(2, $"user.json?username={username}", true, new RestGetOptions
    {

    });
    return response;
}

Looking at the doco (community.telligent.com/.../show-user-rest-endpoint), I should be doing it this way, but it never returns a username

public dynamic GetTelligentUser(string username)
{
    ServicePointManager.Expect100Continue = false;
    ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

    var host = new ClientCredentialsRestHost(
        communitySettings.Username,
        communitySettings.Endpoint,
        communitySettings.OAuthClientId,
        communitySettings.OAuthSecret);

    var response = host.GetToDynamic(2, "users/{username}.json", true, new RestGetOptions
    {
        PathParameters = new System.Collections.Specialized.NameValueCollection {
            { "username", username }
        }
    });
    return response;
}

Updating a user

I followed the doco ( Update User REST Endpoint ) for updating a user, but always says "User not found" or "Lookupusername is required". Doing it by user ID was easy and works fine. 

var host = new ClientCredentialsRestHost(
communitySettings.Username,
communitySettings.Endpoint,
communitySettings.OAuthClientId,
communitySettings.OAuthSecret);

var response = host.PutToDynamic(2, "users/{lookupusername}.json", true, new RestPutOptions
{
PathParameters = new NameValueCollection {
    { "lookupusername", username }
},
PostParameters = new NameValueCollection()
{
    { "_ProfileFields_Address", profileData.ContactInfo.Address },
    { "_ProfileFields_City", profileData.ContactInfo.City },
    { "_ProfileFields_Country", profileData.ContactInfo.Country },
    { "_ProfileFields_Email", profileData.ContactInfo.Email },
    { "_ProfileFields_First_Name", profileData.ContactInfo.FirstName },
}

});

return response;