Delhi Development Authority [DDA] — water leakage in washroom

Address: New Delhi, Delhi, 110075

I have lig flat in dwarka 23, pocket 8, d3 flat no. 7. There is water leakage in toilet. While complaining to dda office in the same pocket, they are saying they will not take care of it. I tried to contact to ddd customer care and they provided dda engineer no. Who never pickup the call.
These flats constructed in 2014. Someone please help me what should i do to fix this problem