Mercedes Menlyn, broke my windscreen during service but refused to repair

I took my car MercedesAMG to Mercedes Menlyn for brakes replacement. When I fetched the car, windscreen was damaged. It was not brought to my attention until I saw it myself. They acknowleded the damaged but refused to repair. Manager refused to engaged me. I escalated to Mercedes Head office and the call was just ignored, including my follow ups emails. It's now 2 months driving with a broken windscreen