As I can see, you have updated the theme. What about Core plugin? Have you installed it via FTP?
Please provide temporary wp-admin access. Create an account via Dashboard (Users > Add new) with administrator role http://prntscr.com/s3rc9m > provide us with username and password via the Private Content area http://prntscr.com/s5mao7 You can use any email for it.
What demo version you can’t install?
