Three columns under three header sections in Microsoft Word (Windows)

Hello, I'm struggling with a work project which involves creating a table of cases in Microsoft Word. Last year, I had it perfect. The Word document was already formatted correctly by the person who had this project before me, and I made sure the Excel document, where I'm getting my data from, was spaced to match the Word document. All I had to do was copy and paste the text, and with only a few tweaks the document was ready.

I'm not sure what happened, but this is no longer working for me even though I haven't changed anything in either document. Essentially, I need to have three sets of data in three different columns under the header. I'm attaching a picture so you can see. If I copy and paste the data directly, it goes vertical. I tried creating and formatting three columns, but no matter how much I play around with the column widths and the indents, I can't get each section centered correctly. I've tried copy-pasting the different sets of data separately but it doesn't let me wrap the text, which means the text spreads out across the page instead of staying within a column.

I'm sure there's a way to do this but I'm at a loss as to what I should be doing. I'm attaching a few pictures so you can see what I'm working with and what's happening. Thanks!