According to Pinduoduo's inquiry, the reason why the mobile phone brands sold in Pinduoduo have no store name is because of the way the products are displayed. Pinduoduo is an e-commerce platform that allows different stores to sell goods on it. When browsing the Pinduoduo platform, you can see the products displayed on the platform. These products will be labeled with their own brands, not necessarily the names of the shops that directly sell these products.