Before you repair, try to find the cause of the settlement....is is poor compaction, water run-off, poor gutter drainage design? There are companies who will inject concrete to lift the steps BUT if the source of the problem is not repaired....the steps will resettle
Had my tree for 6 yrs. before i had flowers bloom on it. Until a neighbor planted hers near in the same area. Airate ! Thin out Cut branches that cris cross. Should help!