This likely depends on your contractual agreement with the real estate firm in regard to repairs.  If the real estate firm is responsible for handling the repairs, covering the cost of the repairs and selecting the individual performing the repairs, I think you can make a good argument that they are also responsible for any damage done by that individual.  You can also make a claim against the repair person himself for the additional damage.  If the repair person is a licensed and bonded contractor, that gives you another avenue for recovery for the damages you suffered.