Why would I receive an alert telling me that I had used all of my vacation time when I never asked for any vacation time?

I would guess you were accidentally set on vacation but you would not have noticed since it applies to online not live games.

Check here to see if you have to turn vacation off. You may want it later if you start playing online games.   http://www.chess.com/home/echess_settings.html

Uncheck "PAUSE MY GAMES! I'm on vacation: please pause all of my games!" then Save Settings

Thanx for the response, but I never checked the "pause" box.  However, that setting now shows 0 vacation time.  I'm not sure who to contact to fix this issue and return my vacation time.  Any suggestions ?

The system automatically puts you on vacation, a day at a time, if you get within an hour or so of timing out any of your games (at least for premium members, which you are). The idea is to save you from losing on time.  Maybe if you had left some of your games alone for too long it happened.

At the end of every page "Help & Support"  http://support.chess.com/

Then lower left  "Contact Support"  http://support.chess.com/Tickets/Submit