Track them down, stalk them and find out their habits and routines, then catch them unawares one moonlit night and kill them with a quick knife slash to the jugular. Drain their body of blood and burn them on a pyre as you dance naked underneath a crescent moon. When the fire dies, scoop up their remains and bury them at a crossroads as you invoke the unholy names of The Devil, Lucifer, The Prince of Lies, Shaitan, and Robert Johnson.

Either that, or just send them a message saying "stop poking me, dick."

Whichever's easier, I guess. Your call, man.