There are several things you can do here because they are in violation of the FTC law of Harrassment and Abuse Section 803(5). You can send a letter to the creditor and the FTC using the following form letter http://www.privacyrights.org/Letters/debt2.htm. or you can pick up the phone and tell them that they are violating the above law. They will probably tell you that it is an automatic dialer, but it is harrassment still the same.
Toyota/Lexus when I called the number back. Everytime I pick up they hang up on me. Making the payments ontime, and more than the minimum. When i did call back their offices were closed. They call me 24/7 after 9pm too!! WHAT THE HELL!