Frequent calls.  No VM left or just silent messages

called today. no message

Rang  got answer machine hung up

I asked if they were from National Grid & she said yes.  I told her I didn't believe her because my caller ID didn't say National Grid & they're not located in Brooklyn or Queens.  Eventually after I asked her to prove she's from National Grid, she hung up.

Got a call CID "New York" .  As always don't pickup if I don't recognize the number.  They didn't leave
a message.