If you notice a debt settlement company marketing illegal savings claims, misrepresenting their services or other questionable practices and they are advertising nationally, what state regulators do you find would be most interested in the information?
Typically the logical place to start on a state basis is the office of the Attorney General.
Don’t be surprised if your complaint doesn’t go anywhere fast. Every state and federal regulation entity has to make decisions about how they allocate resources and budget. They may have bigger issues they are dealing with.
If you received marketing material in the mail, the USPS Postal Inspector seems to take these things seriously as well.