It is definitely AT&T voicemail. It is the number I use to retrieve my wireless voicemail. ASDF above is correct - someone is spoofing using this phone number.
Continues to call leaves no message and no info?
When the caller I.D. showes no name and no information, what kind of official business would opperate in this manor?
This is were I feel the phone companys should have some way of stopping these sort of actions fast and with criminal recorse.