Stop spam members in directory site?

I have a site using Directorypress v7 and have so many users listed in it with no listings. Im not talking a few hundred but thousands. Looking at the emails and user names they obviously just spam hoping to get a link back. Any ideas how to get rid or to stop this? Also on the same site I get many people trying to list their site that dont fit the directory. I keep deleting but they create a new user and try again. I stopped the free listing I had hoping this would stop this but I still have loads of listings to approve. I am confused how the listings get to the ‘approve’ stage when they havent paid for the listing . ANy ideas?