Spam Users

Hello:

For nearly a month now every time I come into the office I will have about 20 emails informing me that a new user has registered on our website. It’s very obvious that they are fake because they all put their name as their agency name and in the field that asks what they intend to use the information for, they put two random letters. I added the SI CAPTCHA Plugin and there was no difference so I removed it. What else can I do?

Thank you

https://ww.wp.xz.cn/plugins/s2member/