My final battle with cold callers was to get rid of the home phone. Only one who ever called was them or bill collectors. So my wife and I use our cell phones. For now cells seem to avoid most these kind of calls.
But back in the day when I had a home phone I would get calls asking for a MR. DeCurtis. I could simply tell them they had a wrong number, no DeCurtis' at that number. They got the name from anything I might have filled out using my middle initials (yes I have 2 middle names) One initial is D. and the other is E. So they would see DE Curtis and think it was DeCurtis. This has helped me so many times in the past. =)