Why are the saved submissions displaying blank?

Hi, 

I am new to Jotform and have only sent a couple forms out for clients to fill in information. I noticed that a client recently submitted the majority of their answers and then when they came back to fill in the final responses that they had left blank, their answers they had submitted were not listed. Can you give me a run down of what to expect when clients submit answers and different intervals? 

Are you referring to the saved submissions of the form that are not yet submitted? I see that there are several sections setup on the form and the last section is displaying the Save button. Could you check if the form submissions are being saved correctly by clicking on Save button by the users? Instead of using section collapse fields, you may try adding page break fields to the form to make the form as a multi page form so that the users should be able to save the submission data.

https://www.jotform.com/help/119-How-to-Create-a-Multi-Page-Form-with-JotForm

Thanks!