Call History/Download problem

Does anyone else have a problem with downloading call history as a ".XLS" file from the webpage phone portal and opening it in Excel?  Do you get an error trying to open the file it generates?

More specifically, after logging into your account, select "Phone" under the "Manage Services" menu at the top of the page.  Select one of your active phone lines in the "Phone Panel for..." drop-down list.  In the left-hand navigation panel, select "View Call History" and wait for the page to populate/update.  Then, from the "Download as..." option at the top of the call history, select the file type of ".XLS" and click on the "Download" link.

The resulting file that gets saved is named "CallHistory.xls", and when I double-click the file it launches my standard/stock Excel 2010 and tries to open it.  But then an error message comes up stating that it can't open the file because the data "is in a different format than specified by the file extension" or that the file may be corrupt.  Yes, I get the option to continue - but try explaining to staff that this is always okay to do when they've been trained to *not* continue on an error for safety/security reasons.

If I open the file in Notepad (changed the extension to ".TXT"), its easy to see the file clearly does not contain Excel type data but instead contains XML data.  If I then rename the file extension to ".HTM", it opens nicely in a web browser.

So the issue is...  how should Comcast fix the download feature?  It would be nice to get the file as a true Excel data file, but they already have an option for a .CSV file which *can* be opened in Excel without a problem.  It would be better to have them change the option in the drop-down from ".XLS" to ".HTM" and then simply create their existing ".XLS" file with a ".HTM" extension.

I've tried explaning this to Comcast technical, but am getting no where.  They keep telling me it works just fine (and probably because they ignore the error and tell Excel to load the file anyway).  So I'd would like to know if I'm off in left field, or how many others have tried this feature or what.