Do pages disappear if plugin is removed

Hello anyone! Hope you are doing great, I’m kind of throwing punches in the dark here, one of my clients asked me to modify some content on his wp site, one of the pages, I can’t access it from the usual wordpress ‘pages’ function in the dashboard, all I can see is a tag at the beginning < This site was created in Webflow. > the thing is I don’t see the plugin installed on his wp site. I think maybe they stopped paying and just removed the plugin. Would this be the case?, and if so, how do we modify this page’s content. Would we have to install the plugin again, and cancel a fee?
Thanks in advance, sorry if im asking too many questions, not very experienced with wordpress and much less with webflow pages.

edit : typos