who are these people who keep calling

Called me many times per day but nobody say anything.

I've gotten a few of these the last week. Answered today and they said it was Verizon offering me the Fios service.  After going through the offer, they asked for a Social Security #. I didn't give it. So the asked some generic questions to prove my identity.

I was then transferred to someone else who said with the info I provided, they cold not verify my identity. They again asked for my Social, when I again refused they asked me to send fax them 2 forms of ID.

I just hung up.

I have received a call from this number several times over the last several days.  I pick up and no one responds.

I've gotten several calls also. Now one speaks when I answer.