Who keep calling me without any answer?

I tried to 411.ca it and find out who it is... but got nothing. Apparently, the number doesn't exist... it could at least say 'private' or 'undisclosed' or something to say they don't want to give their name...
Either way, there is no reason for a car call center to phone me because my car lot emails me directly... and has previously phoned me directly, and their name as saved in my cell phone appears on the display so I know it is them.
They also like calling me while I'm at work... which even if I did hear the call, odds are I won't answer them unless they get lucky and catch me on break.

June 21, 20121/2 dozen calls in past 2 days...line dea when you answer and if you call the number - it doesn't "compute"...weird

this number calls me once a month excatly every 3rd saturday of the month and always around 6pmI dont bother to pick up

I have been getting this number on my missed call list once a day for the past 4 days. They always call during the day when I am at work and no messages are ever left. SO ANNOYING

this number calls me once a month excatly every 3rd saturday of the month and always around 6pm
I dont bother to pick up