Sort function - line integrity compromised

Background: I have an excel spreadsheet that I use to track customer interest in certain products that I sell. I have one column for the date I spoke with the customer, a second column to track which customer indicated the interest, a third to indicate what product they were interested in, and a fourth column for brief call notes. I use the sort function to sort the data by date to see what products customers were most interested in recently. I also sort by customer so that I can review all the products that the customer considered in the past.

Problem: When sorting, I have been highlighting all the cells in question, but for some reason, excel is not honoring the integrity of the data in the line. When I sort, I expect that all of the data that is in line L to stay together in one line. Instead, the integrity of the line is violated. The result is that the dates of the calls no longer match the customers whom I spoke with (i.e. the date in line L that used to be paired with the rest of the info in line L is no longer matched with line L).

Can anyone tell me the following:
1) How can I fix/avoid this problem?
2) Is there any way to recover "line integrity" after it has become jumbled?

Yes, I definitely had all lines/cells highlighted. It's very puzzling how it could possibly happen, but it does.