Air India - Flight related issues

My sister's flight was booked for **th March from Bangalore to Delhi and was a connecting flight. Bangalore to Hyderabad was Air India and from Hyderabad to Delhi was a different airline. It was an early morning flight and suddenly one night before at around * pm we received this message that the flight has been rescheduled. This is not the first time that this issue has happened with Air India. We tried contacting Air India customer care because the * flights originally had a gap of * hours but after this delay of Air India the gap duration left was only ** mins and it was impossible to board a flight in such short duration. Instead of helping us out the customer care representative kept saying that our Air India booking is only from Bangalore to Hyderabad and they are responsible only for that. They were not at all bothered about the other connecting flight which we were missing because of this delay of this flight. We had a very bad experience. And in the end, when we have left with no other option we had to cancel both our flights Bangalore-Hyderabad plus Hyderabad-Delhi and make another booking for this travel. I swear on not travelling by Air India again. It was a horrible experience and some action needs to be taken against the airline. There should be a reason to delay flights and a proper and suitable alternative should be provided if this situation arises which they were not able to provide. An action has to be taken else they will keep making fool of us.