I have been getting calls from this number at least twice a day and it started two days after I took my truck to a Chevy dealer for service. I just called 1-800-864-8601 as Jad had suggested on a previous post back on March 4th, 2009 and added my number to their do not call list. I will see if it works and let you all know. Their message did say it could take a couple days before the calls stop.

Called asking for primary driver of CTS Caddi.  After a few questions he hung up

3rd call we've recd from Cadillac engineering

Caller ID says General Motors.  Call every couple of days and never leave a message.  Pain in the butt!

Just bought a GM car, it is them who keeps calling. They should warn you that they are going to obsessively call you, as ti not tick you off.