Who knows what Shenzhen Jinyi Technology is like? What does this company do? Is it formal?

You mean Shenzhen Jinyi Technology Co., Ltd. They are mainly engaged in the production, research and development, manufacturing and sales of ETC, RFID, ICC and manual charging handheld POS machines. The company is headquartered in Tsinghua Information Port, North Zone of Shenzhen Nanshan Science and Technology Park. I don't know if the company is formal, but it should be quite formal. It seems to be a national high-tech enterprise (Baidu's), and the scale should be ok, with branches in Guangzhou, Beijing, Wuhan and Hangzhou. You can go to official website to find out the situation, instead of asking here.