Trouble creating-and-including AND excluding entries in TOC

I am updating an existing document that was created long ago by someone who is longer with our company. The previous author/editor knew even less about FrameMaker than I do.  

The single document is not part of a .book file and it contains what appears to be a generated TOC on its own (again, self-contained) pages 2 and 3. 

I HAVE found Insert > Table of Contents > Create Standalone TOC, but can't find a way to effectively edit or revise the setup of the already-existing, self-contained table of contents. 

• While experimenting with Markers and Paragraph Formats, I accidentally made one important TOC entry disappear, which makes me think this TOC that I'm trying to repair/update IS dynamic/updatable, and not just dead text that someone typed manually. 
• I have also tried to delete a TOC entry that displays only a page number but no other text (included image). I have searched its page in the body of the document and accomplished nothing by looking for every possible Marker or wrongly-Paragraph-Formatted line on that page. 

As with my previous cry for help, I can't really include detailed examples of our "proprietary content".

Any help would be very, very, VERY much appreciated. 

Thanks,

Lew Yedwab