Do they sell Wang Jia Sha in Tangzhen, Shanghai?

No. Wang Jia Sha is a long-established Shanghai restaurant and dim sum store, famous for producing traditional Chinese snacks and known as the "Shanghai Dim Sum Champion". Shanghai Tangzhen is located in the Pudong New Area of Shanghai, the store has not opened in the area, there is no such store. The store is subordinate to Shanghai Meilongzhen (Group) Co., Ltd, located in Jing'an District, Shanghai.