How to obtain a list of messages

it.mailupnet.services.MailupSend myService = new it.mailupnet.services.MailupSend();

... // perform login by means of LoginFromId(user, password, myConsoleID) method and obtain accessKey value
 
string s = myService.GetNewsletters(accessKey, 1); //Returns all that have been messages created within list 1
 
...//extract errorCode value from received response; 
 
if (errorCode == 0)
{
  // enter here if request was successful
  // then received response can be parsed to retrieve the messages that belong to specified list
}