Initially Incorrect

(I am a “mononym.” That is, I only have one legal name, which I tend to use as a surname.)

Caller: “Please could I have your first name?”

Me: “I don’t have a first name, only a surname: [My Name].”

Caller: *thinks for a second* “What about an initial?”

Me: “An initial? For a first name that I don’t have?”

Caller: “…”

Me: “…”