INTL GATEWAY...ALWAYS NOTHING ON THE OTHER END

I LET IT GO TO ANSWERING MACHINE, DUE TO A LARGE VOLUME OF NUISANCE CALLS IN THE PAST COUPLE OF DAYS. I HEARD SOME BACKGROUND VOICES AND A YOUNG WOMAN'S VOICE HUMMING IMPATIENTLY FOR A FEW SECONDS, THEN SHE HUNG UP.

I keep getting phone calls from this damn number who the f*** is this?  I will kill these damn w***es.