Indian Railways — train diversion without intimation.

I have booked a journey with pnr no. [protected] train no – 07092 from darbhanga (Dbg) to secunderabad (Sc) for my father, mother and my 2.5 year son. When they arrived on source station (Dbg) there was an announcement that the train is diverted from darbhanga (Dbg) to samastipur jn (Spj) station which is 75kms from darbhanga (Dbg) station. But they didn’t send any message or call with prior intimation. It is difficult for senior citizens to travel with 2.5 yrs kid from one station to another station in last minutes. We spent our money to travel from one station to other station. Who will responsible if they miss the train or if they get into any trouble. We logged a complaint as well in the samastipur jn (Spj) station and the complaint no is 25. We lost money, time and mental tension for senior citizens.
So we demand a compensation and a proper explanation from railways.