As a former phisherman, replying AT ALL, only tells this phisher that he's got a live fish on the end of his hook.... PROVERBIALLY tell em to XXXX off, ie, ignore their bullshit and go on with your day.
Sure, you could give everyone who talks to you a curtious response, but i akin this as to the crackhead asking for change, he didnt dignify a response with his first statement, he aint owed anything.