What is the ruling on giving a portion of the dowry (shabaka) to someone who mediated its recovery, and is the claimant mistaken or correct in their actions?

The entire set (jewelry) belongs solely to the suitor if the engagement is broken, regardless of whether the breakup was due to him or due to the fiancée. There is no harm in seeking to reclaim it and in seeking assistance from others in doing so. What is given to someone who helps in the reclamation is not forbidden; rather, it is a permissible ju'alah (commission/reward) if the rightful owner is wronged.