Who called from 3609910910

I have received several calls from this number on my home phone during the day while I'm at work.  No one ever leaves a message.

Got this call today; the man on the other end of the line identified himself as Frank from National Home Protection, a company that is now defunct, according to my research on-line. Hung up quickly!!

Got a call from them and they hung up as soon as I said hello, I called back and the number was not a working number?

Got this call a few minutes ago.  Caller just left a voicemail message but no messages was left.  I tried calling back and the operator came on and said, "Number is disconnected and no longer in service".  Strange?

Area code is from Olympia, Washington.   Wonder how this person is getting our phone numbers?  They don't leave a message.