My friends who own or help run local small businesses have told me it happened to them, so I believe my friends. Of course, it's not explicit extortion like "pay us $500 a month or else", so there's no hard evidence for anything. Instead, magically not too long after they refuse a cold-call sales pitch, they have a bunch of bad/fraudulent reviews surface to the top of their Yelp page and then get another sales call later on.