Sun Ka (pseudonym) has been going through a run of bad skin days. Her face got red, itchy, dry, and broke out in a rash of zits after she stopped using a facial mask she bought via the social networking platform WeChat from a Henan-based seller named Zhou Menghan.

A doctor diagnosed allergy and dermatitis, but the diagnosis didn't put an end to Sun's mental and physical pain. "I was Zhou's fan even before she started selling facial masks. I really trusted her," Sun told the Guangdong-based Southern Weekly.

However, after Sun used the moisturizing facial mask for two months, she found that she had started to grow a moustache, and her sideburns had grown thicker. Like other fans, Sun first thought that she might not adjusting properly to the mask and believed that "if I kept on using it, I will have a great-looking face like Zhou's."

But her fantasies were eventually put to rest. When Sun tried to demand an answer from Zhou, the latter disappeared, leaving Sun with nothing but a 7,438 yuan ($1,200) hole in her bank account.

WeChat is one of China's most popular social media platforms, but users are increasingly finding it crammed with promotions for various products by people trying to peddle their products to their friends.

Many sellers are part of pyramid scheme-type businesses, and lure others to join the business by showing off the money they earn and the quality of their product.

Sun's misfortune, together with that of other victims, has resulted in a public wary about quality problems associated with products sold via WeChat, and has raised concerns among experts over lax supervision of this new market.

'Fans economy'According to Sun, Zhou attracted 120,000 Sina Weibo followers since March 2014 after posting her selfies online. With numerals fans consulting her about secrets of skin care, she kept saying that a silk mask she used every day made her face glow "better than all the famous brands."

In July, Zhou, who claimed have returned to China from Vienna, opened a WeChat account and began selling facial masks.

The masks were sold without a government license or information of the manufacturer for the price of 19 yuan apiece. Zhou said that the mask's recipe was derived from an experienced traditional Chinese medicine doctor and produced by a factory she had specially chosen.

Zhou promised that the mask contains no harmful ingredients such as heavy metals, and said she would pay compensation of 100 times the cost of the mask if there were any problems.

Having seen the screenshots Zhou posted on her WeChat with positive comments supporting her mask, Sun placed her first order in September 2014.

Facial masks are one of most popular products sold on WeChat, along with cosmetics, clothing, snacks and jewelry.

Suspicious mask sellerAnother victim Zhang Qian (pseudonym), one of Zhou's friends in Vienna, said that Zhou also released a quality report from the Guangdong Testing Institute of Product Quality Supervision to her fans, which was meant to dispel concerns over the mask's safety.

However, when Zhang saw victims' pictures online, she cried, saying that "I did not expect that she would fool me." Zhang said that she was furious after Zhou deleted her WeChat account without apologizing.

Zhou's classmates in Vienna told the Southern Weekly that she did not graduate, dropping out of school without telling her professors. Another source added that the mask she claimed "originally cost 140 yuan a piece" was actually purchased for 6 yuan.

The newspaper said that the manufacturer mentioned in the quality report, however, does not produce cosmetics, while the company's manager said that his company had never received any orders from Zhou.

An engineer surnamed Hou from the Guangdong institute said that they are only responsible for testing products, not for verifying clients' identities.

Zhou could not be reached for comment as of press time.

Regulatory gaps"If a skin care product claims to generate immediate benefits, we should be cautious about using it," said Ma Xiaoling, a doctor in the dermatological department of Nanjing Maternity and Child Health Care Hospital in Jiangsu Province.

Ma said that a chemical called glucocorticoid can be added to cosmetics to whiten and lighten skin. However, the same chemical can cause the allergic symptoms experienced by Sun once people stop using it.

Pan Zequan, a sociology professor with the Central South University, said that "this is a typical market strategy - targeting friends - as we tend to trust people in our circle."

However, Zhou's case shows the difficulty of handling fraudulent WeChat schemes: Some of the victims have refused to reveal their true identities, some do not want to shoulder the cost of litigation, some are Zhou's friends who are reluctant to give testimony, while others are Zhou's agents, who have also gone into hiding. The newspaper cited another case involving a victim in Jiangsu who complained to their local regulator only to be rejected with the explanation that "the case did not happen here," while another victim in the Inner Mongolia Autonomous Region filed a report with a local public security bureau but was told that "you should turn to the police where the mask came from." However, Henan public security authorities said that victims should file reports with their local police.

Yao Jianfang, an analyst from China's Electronic Commerce Research Center, told the Xinhua News Agency on April 19, that WeChat platform should tighten supervision of its sellers. For example, a strict review mechanism should be established to register WeChat shops which sell products and publish information of purchasing, logistics and reviews to consumers.

A staff member with the customer hotline 12315 told the Hunan-based ldnews.cn that, although the government has released regulations supervising online shopping, they are targeted at e-commerce platforms such as taobao.com and JD.com, adding that no specific regulations apply to trades completed on WeChat.

"WeChat is a private communication tool. Sellers can delete products' information freely, making it difficult for victims to defend their rights," said Qiu Meisheng, a Hunan-based lawyer, suggesting victims keep their trade and chat records and defend their rights in accordance with China's Consumer Protection Law.

Newspaper headline: WeCheated