1. How do I file a grievance with Medicare? Posted on September 11, 2017 at 12:30 pm.Written by advantage_admin You may give us feedback about your Medicare health care or prescription drug plan. This information will help the Centers for Medicare & Medicaid Services continuously improve the Medicare program. Medicare Post navigation 1. How do I file a grievance with my Triple-S Advantage plan?2. How do I file an appeal?