Non-profits (and politicians) aren’t required to abide by the do-not-call list. As for vendors, they’re breaking the law. What’s particularly egregious is the recorded calls that tie up your line — they don’t disconnect when you hang up. Suppose you had an emergency! There’s a certain furniture store that pulls this trick. They’ve lost my business for life.
One solution that sort of works in not to pick up unless you recognize the caller ID.