I am receiving emails with .wav attachments
that have been created on a VoIP telephone
system.

I know the telephone number (it's include in
the text of the email) and if called it always
goes to the voicemail.

Why I receive the voice/emails can only be
resumed as an error, done by whoever set
up the service.

Is it possible to determine who the provider
on the Voip number is? If so, how?

Nick.