Faber Heatkraft — Not absorbing steam exhibitted while cooking

The Chimney has stopped absorbing the steam even after cleaning the chimney. I hd logged a complaint 3 months back where an engineer had come after 2 weeks of registering an urgent complaint and he returned as there was no supply of electricity and said woud return once the electricity is available (2 hours). He never showed his face after that. The issue still persists and i dint get any proper response from them.