Miami Consulate Requirements - No petition found - Public Liaison Refusing to Answer Questions

I don't have my grandfather's petition for citizenship and the Public Liaison says that they cannot provide a letter of that sorts, so I then asked her where to get the letter and she's refusing to answer any of my questions and I'm getting extremely frustrated that she can't tell me where to get the letter from that the Italian Consulate in Miami requires me to have. (An official statement from the USCIS DC office and the Field Office in the Court District where my grandfather was living while naturalized, saying that they do not have the Petition.). She is refusing to answer my question, so my question to you all is how do I get those letters? I'm getting extremely frustrated and idk what to do