Dictaphone's missing one moving message (8)
I believe the answer is:
dispatch
'message' is the definition.
(dispatch is a kind of message)
'dictaphone's missing one moving' is the wordplay.
'missing' suggests deleting specific letters.
'moving' indicates anagramming the letters (letters are moved around).
'dictaphones' with 'one' removed is 'dictaphs'.
'dictaphs' with letters rearranged gives 'DISPATCH'.
(Other definitions for dispatch that I've seen before include "Send promptly; murder" , "Military report (sent in haste?)" , "Execute" , "Kill, send off" , "report I preferred" .)