Defective Water Closet from RAK Ceramics not being replaced

I purchased 3 sets of Water Closet of RAK Ceramics India Pvt Ltd from their local dealer and installed in my bathrooms 8 months back.
The Water Closet installed in my house broke within 6 months of installation. out of 3 sets installed 2 broke of its own. Crack developed within 6 months and complain was lodged with company but they refused to replace the defective pieces and are not responding properly to my complaint.