Random calls from a number with all zeroes?

Does anyone know why I might be getting calls from a number with all zeroes as the Caller ID? They always leave a voicemail, but there is no sound on

Does anyone know why I might be getting calls from a number with all zeroes as the Caller ID? They always leave a voicemail, but there is no sound on the voicemail. It's really bothering me, any advice would be very helpful.

or:Does anyone know why I might be getting calls from a number with all zeroes as the Caller ID? They always leave a voicemail, but there is no sound on the voicemail. It's really bothering me, any advice would be very helpful.

Tags:sound,always,