Saving a submissions and submissions completion time

Is there a way you can save a submission and come back and complete it letter without losing the data you saved? 

Yes, there is a way to accomplish that

By adding an edit link in an autoresponder:

http://www.jotform.com/help/40-How-to-Let-Users-Update-Their-Form-Submissions-at-a-Later-Date

By using Session ID method:

http://www.jotform.com/features/save-and-continue/

Your other unrelated question was answered on this thread