Vastek Group interview questions

There was a phone screening to confirm that I was comfortable with the wage and task type. They seem to be working with another staffing agency (GlobalLogic) for a contract with a larger client (Google). Then there was a general interview where they confirmed my education and asked a little bit about my experiences. The next stage involved a google meets video call in which I shared my screen while proofreading and editing a paragraph to confirm my command of the English language. After that step, I got an email asking for personal information like DOB and last 4 of my social. What made the experience confusing is the sheer number of different people contacting me. Each time I got an email or an interview, it was with a new person. This made it hard to keep track of. I mentioned it during one interview and the interviewer laughed it off and said he knows it seems like a scam. I got the job but the whole recruiting process seems like a scam.