BWSSB
Sewage Drainage leakage

I am resident of BCMC Lyt, raghuvanahlli 5th main, adjucent to us BCC lyt, there is a leakage in sewage line from BCC lyt which si flowing into our BCMC lyt, I had given a complaint and BWSSB is telling thath they will not do as it not handedover to them, it was under BDA first and then no it is under BBMP. I have approached BBMP first and the adivsed to contact BWSSB and now BWSSB is telling they will not do. Pls help out whom to approach.