At 6.45pm on 5 December 2014, Ben Edelman – an associate professor of business administration at Harvard Business School who works on internet architecture, online advertising and consumer protection – phoned Sichuan Garden in Brookline, Massachusetts, to put in an order for Chinese food.

He ordered shredded chicken with spicy garlic sauce, sauteed prawns with roasted chilli and peanut, stir-fried chicken with spicy capsicum and braised fish filets and Napa cabbage with roasted chilli.

The order should have come to $53.35, according to the menu he had seen online, but when he checked the bill he found that four extra dollars appeared to have been added. So Edelman emailed the restaurant to find out what had gone wrong.

Ran Duan, the manager of the bar in the restaurant’s other location and the son of the restaurant’s founders, quickly replied to apologise, explaining that the website’s prices were out of date.

For many people, that might have been the end of it. But Edelman has a very particular set of skills. Skills he has acquired over a long career. Skills that make him a nightmare for people like Duan.

And Edelman went to war.

“Thanks for the reply and for explaining what went wrong,” he wrote, in emails obtained by Boston.com. “We enjoyed the food, but we don’t need to trouble you for an updated menu.”

Then things got serious, fast. “Under Massachusetts law it turns out to be a serious violation to advertise one price and charge a different price,” Edelman continued. “I urge you to cease this practice immediately.” He suggested the restaurant remove its website entirely.

“In the interim,” he said, “I suggest that Sichuan Garden refund me three times the amount of the overcharge. The tripling reflects the approach provided under the Massachusetts consumer protection statute, MGL 93a, wherein consumers broadly receive triple damages for certain intentional violations.”

“Please refund the $12 to my credit card. Or you could mail a check for $12 to my home.”

Duan responded an hour or so later, telling Edelman that his is a “mom and pop restaurant” and plaintively offers to honour the website price. But it was too late for hearts and minds with Edelman.

“It strikes me that merely providing a refund to a single customer would be an extremely light sanction for the violation that has occurred,” he replied. “To wit, your restaurant overcharged all customers who viewed the website and placed a telephone order – the standard and typical way to order takeout. You did so knowingly, knowing that your website was out of date.”

“You don’t seem to recognise that this is a legal matter and calls for a more thoughtful and far-reaching resolution. Nor do you recognise the principle, well established in applicable laws, that when a business intentionally overcharges a customer, the business should suffer a penalty larger than the amount of the overcharge.”

The exchange went on in the same vein. Duan offered to refund the difference, and the $12 which Edelman demanded, to no avail.

At one point, Duan asked the question on the top of everyone’s mind. “You seem like a smart man,” he wrote. “But is this really worth your time?”

“You’re right that I have better things to do,” came Edelman’s response. “If you had responded appropriately to my initial message – providing the refund I requested with a genuine and forthright apology – that could have been the end of it.”

“The more you try to claim your restaurant was not at fault, the more determined I am to seek a greater sanction against you.”

Edelman is, you may be surprised to learn, no stranger to conflict in the online realm. In a March 2014 profile of him in Bloomberg Businessweek, Edelman’s mentor, Alvin Roth – a Nobel laureate in economics – described Edelman as “the sheriff” in the wild west of the internet for his tenacity in calling out corporate misdeeds online.

Edelman’s investigations, according to his Harvard profile, include uncovering Google Toolbar tracking users even after it is disabled, and Facebook revealing user data to advertisers despite promising they weren’t. Richard Boscovich, an assistant general counsel at Microsoft, described him to Bloomberg Businessweek as “the Doogie Howser of online investigative work”, as he started his efforts in that field at a young age.

Speaking to Boston.com, Edelman said that he usually looks for business malfeasance by larger companies. “It certainly seems like a situation that could call for legal redress,” he said. “But this is a small business in the town where I reside.”

But in a statement he gave to Business Insider, Edelman said that he thought the Boston.com piece missed the benefit that diligent consumers provide in looking for overcharges. “We all rely on trust in our daily lives,” he said, “that when sales tax is added, it actually applies and equals the specified amount; that the meter in a taxi shows the correct amount provided by law and correctly measures the actual distance; that when you order takeout, the price you see online matches the amount you pay in the restaurant. We all take most of this for granted.”

“I’ve been pretty diligent in holding large companies accountable for their false statements of price and other attempts to overcharge passengers. Should all small businesses get a free pass? Some people seem to think so. I wonder if that really makes sense,” he said.

Duan told the Guardian that he was trying to be professional. “Honestly, this is the most unusual customer exchange I’ve ever had,” he said. “I did my best to try to rectify the situation, but he seemed very vindictive and wanted more.”

He said that he bore Edelman no ill will, however. “At least he said the food was delicious. I wish no harm on this guy.”

The full exchange can be read here.

Edelman posted an apology to his website on Wednesday. “Having reflected on my interaction with Ran, including what I said and how I said it, it’s clear that I was very much out of line,” he said. “I aspire to act with great respect and humility in dealing with others, no matter what the situation.”

“Clearly I failed to do so. I am sorry, and I intend to do better in the future.” He added that he had reached out to Ran, and intended to apologise to him personally.

