User Role Editor/Membership Can either of these stop users being able to post new pages or posts?

Hi

Javi has been trying to help me just now to stop my multisite users from creating new posts or pages on their sub sites, using User Role Editor. His theory was if the edit_posts/edit_pages capabilities were unticked, those users should not have the ability to post new posts or pages, but it doesn't work. Are we using the right capability?

If I don't find a way to stop this, I am going to have a huge policing problem on my hands stopping users from littering their sites up with junk. I only really ever wanted them to have access to a store to post their products.

He also wondered whether membership could be used someone to control this? I already have that installed, so am interested in any suggestions.

Many thanks

Sally