BEIJING - Three vendors on Alibaba's Tmall.com platform voiced strong protest against an official quality inspection report on Thursday after a dispute between the e-commerce website and the regulator.

In an joint letter posted on their Sina Weibo accounts, three outdoor sports stores, including Xundong, Ronggu and Jiubaidu, demanded explanation from the network supervision office under the State Administration for Industry and Commerce (SAIC) over a report released last month that accused them of selling fakes.

The vendors said their stores had been frozen by Tmall since then and they had not received any report or evidence from the SAIC showing what they had done wrong.

"This was like giving us the death penalty without undergoing any trials," read the statement.

If the SAIC refuses to respond, we have to resort administrative litigation to protect our legitimate interests, the statement added.

The latest episode came amid the ongoing salvo between Taobao, the most profitable branch of e-commerce giant Alibaba Group, and the SAIC since the latter published a quality inspection report on Jan. 23 that gave Taobao the lowest rank in terms of certified product rate.

The SAIC sample test showed that only 37.25 percent of surveyed commodities sold on the website were authentic, lower than a 58.7-percent average of major online shopping platforms. Taobao's major rival, JD.com saw its rating at 90 percent.

Taobao fired back on Tuesday and said it was unfairly treated.

It claimed the inspection was flawed in logic and contradicted previous data, pointing out the authority only made a sample of 51 items which cannot represent the enormous trade volume on the platform.

In an official response on Wednesday, Taobao said it will file a complaint to the SAIC based on accusations of a senior official's improper supervision.

"Director Liu Hongliang followed improper procedures and his legal assessment was emotional," Taobao said, "He reached a conclusion that was not objective, bringing a negative effect on Taobao and e-commerce businesses."

"We welcome any supervision that is fair but oppose nonfeasance and random or malicious official actions," the post said.