I have a mystery....
There is a mailbox that was once enabled for UM with the incorrect number. We disabled Unified Messaging on the box but now they are still receiving Voice Mails in their inbox.
I've checked in powershell with get-mailbox "username" | fl and UMenabled is set to false. The mailbox also shows as not enabled for UM in the Exchange console.. No extensions shown in 'Email Addresses' (EUM) field.
The Voice mails that come in are sent from MS Exchange to the mailbox. Looking at the headers there is nothing indicating that the message has been forwarded from a different address..
It's attack of the phantom voice mail... has seen anything like this before?