Vent Air (internation Range Hood) - chimney

I have purchase one no of chimney make Vent Air (Benz Curve) from Jagadhatri Trading & Engineering, Baghajatin Road, Siliguri on **/**/****. As per their commitment they will do three nos of free servicing within the year. However they done only two nos of free servicing at the schedule period. At the time of *rd servicing i contact with them within the period, but the not response. Further i contact with them on **/**/** and they will come **/**/** and told me the date has been over, so free servicing will not be provide. In this circumstances i request your good self that the matter will be solve sympathetically.