1) A "BARRED" response when posting to txtNation can mean one of three things:
i) The user has sent a STOP message
ii) The user calls us and requests to be added to a barred list.
iii) The MSISDN is a dummy number used by txtNation for testing, e.g. 44777777777.
If you receive this, do not re-try the message as they are permanently blocked until the user opts back in, removing them from the barred list.