how can i complain against B.K Sanitary Emporium , new delhi?

[Anu]

i purchased some kajaria wall tiles from B.K. Sanitary Emporium, Bhogal. new delhi....i was promised a cash back if any piece of highlighter remained...!...getting bck home...i found some pieces defective ...wen i tried to return dem dey cunningly refused..!...d shrewd shopkeepers jz clearly denied to gv me ma right to seek a redressal!!..i wnt to complain against dis shop...wt shud i do??