New Delhi, April 8 -- Bengaluru: As the summer heat soared this year, Vishal was on the hunt for a cooler. But instead of heading to Amazon, Flipkart or any other e-commerce platform, he sent a message to a private Telegram group to ask for a "deal."

In that same group, Samrat was looking for a deal on perfumes, while Ashutosh wanted a discount on headphones.

Vishal, Samrat and Ashutosh aren't ordinary shoppers hunting for bargains. They are part of a sophisticated underground network of product reviewers, who receive heavy discounts or sometimes even free products in exchange for leaving glowing five-star reviews on e-commerce portals such as Amazon and Flipkart.

A hidden world of fraud is flourishing in the depths of Telegram and pri...