I have been calling GetMemberMessagesCall with the MessageStatus not set and nothing is being returned.
According to the documentation
"If this field is omitted, both answered and unanswered member messages are retrieved."
GetMemberMessagesCall g = new GetMemberMessagesCall(apiContext);
g.SenderID = memberid;
g.MailMessageType = MessageTypeCodeType.All;
g.DetailLevelList = new DetailLevelCodeTypeCollection();
This has been tested against different memberid which are known to have answered and unanswered messages. The call returns data correctly when the messagestatus is set.
Seems like I will have to call this twice with the message status set to answered and unanswered to get all messages which seems daft.
Assuming this is just incorrectly documented unless anyone knows different?