Air India — financial loss and mental stress due to wrong information provided

Address:

Mumbai City, Maharashtra, 400081

Our family of 3 had a flight from mumbai to bgdogra with a stopover and change of flight via delhi. The flight from mumbai got cancelled (Ai0348 on 7th april 2019) after a delay of 2 hours and as a result we missed the connecting flight to bagdogra (Ai0879). We were then shifted to a new flight to delhi.
We checked multiple times with their staff about another connecting flight from bagdogra as we had to reach there on the same day to continue our trip to bhutan from there (All hotel and trip bookings were made accordingly). They assured us that everything will be taken care of and that a connecting flight will be arranged.
After reaching delhi we were informed that there are no flights for bagdogra for the same day and that we will have to take a replacement flight the next day. Had they told us this in mumbai we would have flown directly to kolkata and got a connecting flight from there (Which was possible to do as flights were available).
What was unacceptable in this situation was that they caused us so much stress and financial loss just because they simply did not think to tell us that there are no connecting flights available from delhi on the same day even after we checked with them multiple times. When we argued with them about this they told us that all that they can do is provide accomodation in delhi and a flight next day. No compensation can be provided for the loss they caused us and that all we can is is lodge a complaint with the airlines and hope for the best.
I am writing here not sure how they can be held responsible for their complete lack of respect for their passengers time and money especially since all this could have been avoided - all they had to do was give us honest information.