Just got called from there at 8:00 at night!  Reporting them to the FTC suggest you do the same:
https://www.ftccomplaintassistant.gov/FTC_Wizard.aspx?Lang=en

they call me several times a week and never leave a message.

I called the number back a couple minutes after being called at 5:44 p.m. PST and got a recording saying they are "Meyer Teleservices" and to call back during business hours, 8-5 CST (6-3 PST) to be put on their Do Not Call list. The company's Web site also offers a Do Not Call form:
http://www.callmeyer.com/popups/do_not_call.htm

The Web site says the company does political calling, and is located at 14 7th Avenue North, St. Cloud, MN 56303, 1-800-676-9233.