RAK Interiors Kochi - Refusal to Honour Warranty Obligations

I had a turnkey contract with this company for a modular kitchen. At the completion of the work, they issued me a warranty docket dated **/**/****.
The modular kitchen has four granite tops. I had three months ago noticed a hairline crack on one fo the four granite tops and now it has widened into a crack across the total width of the granite. On examination, I have found out that the gauge and quality of this damaged stone are inferior to the other three granite tops. I raised a complaint with RAK Kochi on ** May ****. Rather than examine the case and check whether the damage is due to the quality f material supplied, they are avoiding their warranty responsibility by saying that the damage is due to wear and tear. They are refusing to send a field officer to verify my claim that the granite damaged is definitely of inferior quality. I request that RAK may be instructed to depute a field officer to verify my claim and to do the necessary corrective work.