Well, if you can't see or select them, it probably makes no sense to have you upload a sample drawing.
Not layers...hmmmm. This invisible text wouldn't be on a background page? Probably not.
Well, open the Drawing Explorer Window, DEW, and navigate to a page that has the invisible shapes. Fully expand the tree for that page. As you select a shape in the DEW, it should show up as selected in the drawing window. Try each shape listed. Hopefully, you'll get a shape that is selected, but no visible content. That ought to be one of your invisible text shapes. You can open it's shapesheet from either the Drawing Window or the DEW. Perhaps there is some attribute set that is hiding the text.
About all that I can think of.
Wapperdude