They call and don't leave a message. When you call back, there is an automated system that gives you the option to speak with Customer Service or to put your number on their do not call list. I chose the to opt out.
This number has called me several times today, and I finally called them back. I got a automated services that gave me a list of options, one of the options was if you want your number on the do not call list press 2! We will see how it goes.