Plugin breaks theme

I was using WC Vendors Marketplace by WC Vendors and some day there was a message in wp-admin that my theme (OneSocial) recommends your plugin. I removed WC Vendors Marketplace, installed and activated yours. It’s very impressive indeed! However, when a user registers as vendor, that breaks the theme for that particular user, i.e. the theme stops showing some menu items, as private messages, profile view, edit, etc. But just for vendors. I checked the user function, it shows the “vendor” function as before, aparently, but it seems the function now is “dc_vendor” instead of just “vendor” as before, I believe that is causing the issue. Is there a way to fix it? I’d love to use your plugin.