Why are there so many lawsuits against Dalian Dingming human resources?

So many complaints about Dalian Dingming's human resources are all due to failure to pay insurance. According to relevant information, most of the dispatched personnel of Dalian Dingming Human Resources are from other places. Only suitable accommodation was arranged for them, and no insurance was bought. After the meeting, the dispatched workers jointly appealed to Dalian Dingming Human Resources.