Soon a law by Government of India is on anvil that airlines can not cancel flights due to "technical problems" .if they cancel then the airlines would have to pay some commpensation to every confirmed passenger.

Also as per present court ruling is that if the flight is delayed, the passengers are to be provided with free snacks/lunch/dinner.

Whenever any company takes money from you or issues some documents, it has to specify the amount colected from you including all taxes.They cannot issue any ticket with out amount mentioned.Even if it is a free ticket, taxes are to be collected form the passenger and should be shown in the ticket that collected amount.Otherwise it is a serious viloation of law.

Suggestyou to take a copy of such document and filea complaints with concerened authorities.