We told you to create staging site and provide Dashboard and FTP access to that site. Once we update staging site and you check that everything is ok then we’ll be able to update production site and we also need FTP, not just Dashboard access.
1) Create a staging site (full copy of the existing site in subfolder or subdomain) and provide link and FTP access
2) Once we finish the update of the staging site, please, provide FTP access to production to update production site. Do the backup of the production site before the update!