The only way to stop them is to cut them out of the equation of your life. It can make the narcissist angry. That evil narc is beneath the level of contempt. Void of understanding and empathy. They just don't care who they step on and hurt in the process.
A recovery from narcissistic sociopath relationship abuse. Remember this - it is an important bit of information. **- being empathetic to a Narcissistic sociopath makes them believe they can get away with anything.