Let it go to voicemail. Played back a snippet in spanish. Apparently this is a block of phone numbers, when backtraced goes to "Arch Wireless" in Los Angeles, CA.
Lookups indicate these are non-valid numbers, indicating a possible VOIP web spoof. One responder has reported that it goes to a menu to "take yourself off the do not call list." Don't know how valid it is.
But it's a junk call. Don't bother answering; because there's no one to tell to f- off.