I have tried half a dozen times now to change the slider but nothing shows up. The slider had disapeared from the homepage and now i have to add it back in on the WPBakery front end editor. After doing this and updating it simply disappears when I reload the page. Is this a common issue?
What version of WordPress and Massive Addons plugin do you use? Make sure that if you use WP 4.9 then Massive Addons plugin is 2.3.1. Update plugin and check if it fixes the problem. If not – provide me admin panel and FTP access to your site to study the problem more deeply.