Notebooks for iPhone Answers

I am unable to make use of Notebook at all at the present time, even though it has worked in the past, and a substantial number of entries have been made that were formerly accessible. For some reason this functionality has disappeared. When I open Notebook, collection titles appear, but when i attempt to access any collection of notes, the screen defaults back to the Apple Touch "mother" screen. I have attempted to overcome this problem to no avail. Help, please!