Section 11-C. Copy of notice of lien to a contractor or subcontractor with respect to public improvements liens

Within  five  days  before  or
  simultaneously  with  filing a notice of lien in accordance with section
  twelve of this chapter or the filing of an amendment of a notice of lien
  in accordance with section twelve-a of this chapter with  respect  to  a
  public improvement lien, the lienor shall serve a copy of such notice or
  amendment  by  certified mail on the contractor, subcontractor, assignee
  or legal representative for whom he was employed or to whom he furnished
  materials or if the lienor is  a  contractor  or  subcontractor  to  the
  person,  firm  or  corporation with whom the contract was made. A lienor
  having a direct contractual  relationship  with  a  subcontractor  or  a
  sub-subcontractor  but  not with a contractor shall also serve a copy of
  such notice or amendment by certified mail to the contractor. The notice
  of lien so filed shall contain thereon or there shall be filed therewith
  proof of service of a copy of said lien upon the parties required to  be
  served  pursuant  to  this  section,  and  failure to file proof of such
  service shall render the notice of lien a  nullity.  Any  lienor,  or  a
  person  acting  on  behalf of a lienor, who fails to serve a copy of the
  notice of  lien  as  required  by  this  section  shall  be  liable  for
  reasonable  attorney's  fees,  costs  and expenses, as determined by the
  court, incurred in obtaining such copy.