This is an add-on to my previous solution.

After saying "Mr. Webdev no longer lives here.", ask that the number be removed from the callling list. That should help reduce the number of calls you get in the future.

Also, just as a general tip, I try to never give out my phone number. I'm surprised by the number of people who will give their phone number when asked by a check out clerk (I know Sports Authority does this).