The pitch was simple: Invest a few thousand dollars in a high-tech scooter sharing company, and watch from your phone as your money doubles, then triples. Some prominent voices appeared to vouch for it on social media, and storefronts popped up in at least eight cities.

But last month, users discovered they were unable to withdraw their "accumulated income" and realized it was a scam. NBC News spoke to people who say, combined, they invested at least $190,000 into Lightning Shared Scooter Co. with little to nothing to show for it. Potentially hundreds more, if not thousands, were similarly targeted.