Ive just had a call from a man that said he was with ACS legal dept. his name was dAustin White and his number?

Austin White from ACS legal dept. how do we get him to quit calling here. Our number is not listed and he got through to our house plus we have a block on our phone to where youmust show yoru number this came up OUT OF AREA and no number....What the hell is going on? his number is 347-709-1652