Do the sales staff of China Mobile Tianjin Company sign a contract with the labor service company? What's the name of that company?

I am a salesperson of Tianjin Mobile Company. The recruitment process is as follows: first, mobile human resources get in touch with the school employment office, then the school organizes registration, and then you participate in the initial test of mobile. If you pass the initial exam, there will be a second interview. If you pass the second interview, it means that you have a great chance to enter the mobile, and then you will be trained in Nanma Road Post and Telecommunications Apartment for one month, and then assigned to the district business hall for one month. Finally, the final exam is divided into three items: oral, written and computer. If you pass, you will be admitted. Mobile signs a formal labor contract with you once a year. There is nothing temporary now, it's all about signing a contract. Take 5 insurance, 1 gold. It's called Zhongtian human resources.