This help page explains more about viewing and downloading your Transaction Log:
Note that the log initially only shows the past 30 days of transactions, so if you wanted to download transaction data for a different date range or for any specific product, you would need to select that date and/or product and click View Log, then you can click Download Log to save that log view to a file on your computer.
Once you download the file, first you would need to unzip it before you can open the unzipped file in a spreadsheet program like Excel. Macs and some Windows computers already have a zip utility built-in, so in that case you may be able to simply double-click the file to unzip it. If that doesn't work, and you're using Windows, you may need to install a zip utility (I like IZArc, which you can get from www.izarc.org).
That's rather strange about the text being cut off as you described, but I could not reproduce that problem myself. It's probably just a one-time fluke, but if it's still happening when you bring up your Transaction Log screen, what browser program are you using, and are you using Mac or Windows?