The Centers for Medicare and Medicaid Services' efforts to halt Medicare Advantage and Part D marketing practices it deems "predatory" have landed the agency in court.In April, CMS published a final rule that limits how, and how much, health insurance companies may compensate brokers, independent agents and other third-party marketers for guiding enrollees toward Medicare Advantage and Part D plans. The people whose pay got cut objected, and a growing number have sued to stop the regulation.