Often at greeting or an announcement mailbox is of a type, where callers can not leave a message.
So I would look through the COS to find the attribute 1:
"NO MESSAGES MAY BE RECORDED FOR THIS MAILBOX"
This is done by: .l cos
Then I would go through the MB that has a active greeting.
To see this do a @L R 8 and choose ALL.
You get a perfect printout of all MB with greeting and number of messages left in the mailbox.
From these 2 hints, you should be able to check this out.
Check also with the costumer!
///doktor