Topic Column Lost Most Content

I have created a document in which the first column, which usually titled Topic, is set as Date. I usually work on this document on my laptop, but last night I worked on the file on my iphone. I am not sure what option I selected, but almost all dates disappeared–I had about 28 dates and I currently see about 4 or so and they are in the wrong row. They are supposed to be on Level 2 Rows, but I see them randomly some of them on the Level 1 Row, others on Level 2 Rows. In many cells on Level 2 Rows, I the calendar icon does not appear for me to add the dates manually. Also the whole column somehow looks like I have selected it because it is always darker, but not all of it.

How can I get the dates back? It will be a major headache to include them again.

If this is a glitch and the file is corrupt now, how can I make back up copies? In MS Word, when I am working on a document, I make copy and change the end of the document title, including today’s date. This allows me to go back to older versions if I need to. Is there an alternative for OO.

p.s. I changed Summary to None in the Column Type option. Now I can add dates to any one of the rows in the first column named Date. But why did the dates disappear randomly? Also the rows are out of order. This is going to cost me my weekend.

Anything there when you try File > Revert to … in the menu?

Or do you have Time Machine or another backup system? (If not, this would be a good time to start:)

SG

I had to redo the file. I have four external drives on which I use TimeMachine.