I long ago put my number on DNC. Still, I get dozens of calls a week, or more, from various places like Home Depot, who somehow were given my number incorrectly by someone whose business line must be similar to my number.
Home Depot local stores I'd call back to tell them to take the number off because it's wrong, and sometimes they would, sometimes not. Usually they'd say they can't do that without permission of the account owner, and won't listen when I tell them that the phone number is WRONG and they're not even calling anyone associated with that account. So I tried their corporate people, and they first tell me to call the stores because they have no control over it, and when I advise them of the responses I get from the stores, they put me on eternal hold and then hang up on me. I filed an FCC complaint about it instead, for each call I got, and eventually it stopped. I guess they didn't like the fines. Periodically I get readded to their lists and file more FCC forms and they go away again.
Same thing with quite a few places. Eventually the FCC complaints make them go away, but the companies themselves won't stop until I do that. Nowadays I don't even try getting them to, I just file the FCC forms for every call that leaves a phone number (I only have a basic phone, no caller id).
But now, it's worse--I get calls for people trying to collect on various people's unpaid debts, who have for whatever reason given out my phone number in their pack of lies they've fed their bill collectors. Same thing for people who are trying to get government benefits/financial aid of various types. Usually one to several a week, though I might go a week or two wihtout one. Whenever I mention to the government people calling that there are lots of these calls by them here, they just say "yeah, we get this alot", so there are apparently quite a lot of people out there falsifying records to claim benefits they aren't entitled to. No wonder I can't get any help; it's all being stolen by those people.
I use an answering machine to screen calls, but usually I leave it (and the phone ringer) muted and just check messages and call people back later, because the incoming garbage is so frequent I can't handle listening to it anymore. Most of the calls are hangups, but sometimes there are so many calls in a day that the machine runs out of memory if I'm not here to wipe it.
I don't know why I attract all these problems, but I sure seem to do it well.
BTW, if anyone wants to do autodialing/etc themselves, I have one of those cardsets that goes in your computer to do this that I'd sell relatively cheap.
No software or anything. Never used it, just was given it by someone else out of a defunct server. Must do some fancy stuff; it's got a pair of 486 CPUs built into it.