I just got a call too. twice in a row and the second time went into vmail and it seemed like the person calling didn't know it went into vmail because there was background sound but no one talking... then hung up.
I've gotten three calls from this number in two days. Don't know who they are but they don't leave a message, so I'm not about to call them back. I never answer the phone anymore--sometimes even if I know the number. It's the 21st century text or email me.