There's an issue with Call History that's been reported to Cox, but I found a workaround until they fix it. Pick the days period you want and then "Download" the items. This will temporarily fix whatever is causing the issue and you'll be able to scroll and display all items.
With Call History expanded, the "Download" link is in the upper right of the grid.
Click "Download" and then click "Download Call History". You'll then temporarily be able to scroll, sort and display items in the selected days period until you change days selection, collapse Call History or close the webpage.