These people are, indeed, illegitimate swine. Victims can contact the FTC, the Federal Trade Commission and report them ... and should do.
Apparently these are the same scum who use a 987 number and I just got finished filing a report with the FTC.
I beg you, if you have been called by these lowlifes, please, please report them to the FTC and to your phone company.
I've recieved numerous calls form this number as well, all with the same results. I just got another call from 1-813-000-7284. Same thing as with the other number, but the automated voice is british, and when I pushed 0 to talk to someone it hung on me.