They are tampering with the Caller ID - It is not a valid # - they are seeking homeowners to sell something.
Try answering like a Business and they'll take you off their purchased phone list forever.
I have received an unsolicited call on my unlisted cellular phone from 16026026000. I do not answer calls from numbers I do not recognize and I do not answer long distance phone calls. This number is both unknown to me and is from outside my country. I do not list my phone number on any list. This company/person should not have access to my number. They have called me twice in 4 days.