Visual Composer Frontend No Longer working

Visual Composer frontend is no longer working while editing pages. All you get is a preview of the Revolution slider on our home page and the text undefined below. Has anyone else experienced this? Does anyone know how to fix it?

I have contacted VC support who say that the Highend bundled VC plugin is conflicting with the standalone VC plugin that we purchased in order to activate support, even though I removed the old version. However, it was doing this before I added the standalone VC plugin.

I can edit okay in the backend.

Instagram widgets in the footer have also stopped working.

Thanks