ISO concrete/foundation work

Hi, Neighbors. The ground under our front porch seems to have shifted at one corner and caused a stair-step crack in the mortar between the bricks in the low wall that surrounds the porch.  The porch is a concrete pad set directly on the ground.  We would like to have the porch stabilized from underneath.  Has anyone had this sort of work done?  Any references or critiques would be much appreciated. Thank you! Diane