This quest can not be done if Not So Safe Deposits is completed. But you must have done that quest up to the last step to get this quest offered. It cannot be picked up after either. It is a one-or-the-other choice of quests.
When you started Crime Pays Someone but want to do Lend a Helping Hand instead, then you can delete the Crime Pays Someone quest and pickup either of the quest. You still can't do both but change your selection that way.
Steps[]
Travel to the zone Echo Caverns into the area Shattered Chasm ( -282, 60, -283 ) Copy/waypoint -282.10, 59.73, -282.55.
Gather 8 "non-trackable" chasm thorn roots. Some approximate locations:
Speak to Evuar Vrottoth in the House of Midst ( 721, -9, -504 ) Copy/waypoint 721, -9, -504 which is of course found from inside the Shadow Haven, 2nd door on the left side ( -522, 3, -260 ) Copy/waypoint -522, 3, -260.