I have a user 7961 G GE (cisco Unity VM)
that deleted a vm message and looking for solutions to get it back. This is an exchange environment
Deleted messages can be recovered or retrieved from the Deleted Items folder of the Cisco Unity inbox. This is useful for when the subscriber deletes the message by mistake. But this can also cause problems if deleted messages get accumulated. They need to be purged at some time interval from the Deleted Items folder. Therefore, the Cisco Unity Administrator needs to set a time period during which you can recover deleted messages.
From this excellent doc;
Unity: Set a Recovery Period for Deleted Voicemail Configuration Example
Hope this helps!