Rift Quest:Endless Correspondence  

The Communiques are on one of the tents in the areas indicated, not on the Courier. Which tent is randomly switched whenever it respawns.

The Shatterbone Courier paths back and forth between the tented camps in the area, and is accompanied by 2 weaker but annoying Shatterbone Escorts. Best way to find the Courier is to watch for 3 mobs walking the roads slowly, or use /target Shatterbone Courier. When you do fight him focus fire on the Courier as he is the one doing most of the damage to you, then burn down the escorts after.