Trapped In Outlook pop-up

[John876]

Hi, good morning,
I have MS Excel for Mac 2011, and I am making changes to a worksheet.

I am editing a cell (making a hyperlink) and I unexpectedly get another window opening. The new window ivies me to "Try Office 365". This window has become the active window. I wish to quit the window, but it has no quit button, so I am tapped.

1) Please can someone suggest the best forum for help with questions about this window (Office 365 Help does not help)?
2) I finally closed the window by going to 'Force Quit' on my Mac, closing Excel, and losing my changes. That's a sledgehammer to crack a nut. Can anyone suggest another approach?

Thanks