Newsnight spoke to a number of affected people who believe their sales have suffered.
A consumer rights activist now wants a UK watchdog to investigate further, as part of an investigation into fake reviews already underway.
Amazon claims to be “relentless” in its fight against review manipulation.
Even so, some of the people targeted feel that it cannot eradicate the problem.
Third-party vendors have sold more physical goods on the Amazon site than the U.S. tech giant itself each year since 2015, according to its own figures.
estimates that £ 23 billion of UK online shopping is influenced by reviews.
Perhaps it’s no surprise that some online retailers are laughing.
“The sad thing is you might have 50 positive reviews, like five star reviews – but if you have one or two one star reviews then it will be very difficult to compete,” Janson Smith, a third . Amazon party seller, told the BBC.
I asked if he would like 20 more five star reviews, if they came with a single one star rating.
False positive reviews on the net are a well-known problem.
Earlier reports have uncovered bogus review “factories” involved in publishing five-star articles in exchange for freebies.
Just last week the Financial Times reported that some of Amazon’s top-ranked UK critics appeared to be engaged in such activities. Amazon deleted 20,000 false positive messages over the weekend.
But some sellers now think it’s the fake one-star reviews that are the new front in review manipulation.
Ella Keyes had a thriving business selling post-pregnancy products on Amazon.
She says she’s had around 60 reviews, almost all of them positive. She was earning around £ 3,000 a month.
Then something strange happened – she received a flurry of one-star reviews.
“At first when the first couple arrived it didn’t have too much of an impact because I had enough positive reviews to make up for it,” she recalls.
“But when more and more started to arrive, I noticed that sales had just fallen off a cliff.
“All that is below [an average of] 4.5 and you are done. “
Ella thinks some of these negative reviews were wrong and the stress has started to hit her.
After a few months, she quit the business.
Janson Smith says something similar happened to him, but he decided not to go down without a fight.
He crossed over to the negative reviews he had received with the orders and realized that almost all of them came from suspicious accounts. He managed to convince Amazon to remove them.
He has since set up an online consulting firm to help other Amazon sellers deal with this and other difficulties.
“I think now the sellers have realized that it was very difficult to pretend to get four star or five star reviews,” he explained.
“So they’re like ‘hang in there, let’s lower the competition now so that our score is relatively higher.’ “
Collectively, independent sellers generate around £ 150 billion in global sales per year through Amazon.
Find the right niche and there is money to be made.
There are legitimate ways to remove a negative review. For example, if a seller receives bad feedback due to poor delivery – which they were not responsible for – they can ask Amazon to remove it.
But there’s a big no-no: Amazon’s rules prohibit trying to bribe or blackmail customers into removing them.
That’s not to say some unscrupulous salespeople don’t try.
A customer – who asked to remain anonymous – told the BBC he had ordered knitting needles which never arrived.
She left a negative review as a result. Upon seeing it, the Chinese seller offered a full refund if she removed it.
I alerted Amazon to the matter. He has since suspended the seller.
Consumer group Which one? says this problem is not unusual and is spreading to other online stores.
“People told us that when they left a negative review, they must have negotiated with the seller or even felt intimidated by the seller to withdraw their legitimate negative reviews,” said Neena Bhati, group campaign manager.
Amazon responded that it wanted people to buy with confidence from its platform and was addressing the issue.
“We have clear policies for reviewers and business partners that prohibit the misuse of our community’s features, and we suspend, prohibit and prosecute those who violate these policies,” he said.
In May, the French Competition and Markets Authority launched an investigation into online exams. Which? now wants to include handling of negative reviews.
The regulator declined to comment.
Whatever he ultimately recommends, it is likely that efforts to stop the manipulation of reviews will never provide more than a temporary respite. Close one loophole, and more will be found.
“I sincerely think Amazon is doing the best job it can, but I think it’s a bit of a cat-and-mouse game,” Smith said.
“Amazon is one step back, and they’re still playing catch-up. “
- Competition and Markets Authority