Who called from 2310000000

Let my answering machine take the call, but they hung up.

I get calls from this number everyday and no answer.

a man said from PG&E, and wanted your ID of gas bill, so he could give you 8% gas bill-tricky call

They whispered, "one...two...three...four...five...six...seven." and hung up

I got a call from 231-000-0000 several times in a week, I answered one time and they asked for Tina.  My name is not even on the phone they were calling it is under my husband's name.  It kinda scared me.