Dead air. Called back the recording said to leave phone number to stop calls. I have found out if you do that they just sell your number as an active number and keep calling.
Just got called.. sounded like dead air at first. Said I filled out some survey online, but wouldn't say which one when I asked him (not that it matters, I'm certain I didn't).
When asked if I'd like to take a survey, I said No thanks, I wouldn't be interested. So he, of course, started to ask me the survey questions. The response of "You don't understand the words 'not interested', do you?" got him to shut up for a few seconds before finally hanging up.
If it weren't a local #, I wouldn't have answered. Sneaky [***].