Alibaba Group has triggered a vast internet protest by small online vendors after introducing steep fee increases on its business-to-consumer site, highlighting the weight the e-commerce group carries in the Chinese economy.

Close to 50,000 people were logged in on Thursday to an online voice chat room for small vendors on Taobao Mall, China’s largest business-to-consumer marketplace, complaining about the price rises and arranging attacks on large Taobao Mall vendors.

Members of the chat room called upon each other to buy large amounts of the same product at the online stores of certain large vendors including Uniqlo, the Japanese clothing chain, and then cancel the orders with complaints to drive down those vendors’ customer satisfaction ratings.