Rest assured that no community courses have been deleted.
We have now launched Community Courses on their own unique website: https://community-courses.memrise.com/signin. To access your community courses, follow this link and use your existing Memrise login credentials.
All progress you made on community courses will still be there and you'll still have the ability to join new community courses, as well as create them. The only thing you won't be able to do is access these on the Memrise app.