When you open the CSV in excel, there is a popup screen that asks what the delimiter is. You need to make sure you select comma. You have it set to semicolon or tab.
Try closing the file and opening again and watch for the delimiter options. However, it may not ask you the second time you open the same file and remember your choice. If that is the case, then rename the csv file to a new name and open it again. Then watch for the popup screen with the options. Make sure to select comma before opening the file.