I have started logging each number they call from on both my home and cell numbers into my contacts. Bad People 1, Bad People 2, etc., etc. That way I never pick up their stupid calls. Hopefully someday someone will get them to stop, but nothing I personally have done has ever worked.
I always answer, and hang up immediately without saying anything. Sometimes we'll do it 5 or 6 times in a row, and I pick up, and hang up every single time. If they've got the time, I've got the time.
:: URGENT ::
Do NOT call this company back … be advised, that once you call them back and confirm your name with them; it permits them by LAW to reinstate the debt back to your reporting credit scores – and the clock starts back to one for seven more years.