Consumer Redressal

I had been booked air ticket through Go air airlines on 21-May-2020 from pune to kolkata. But i have been cancelled the same as Honourable chief minister govt of West bengal announce that airport shall be open on or after 28-May-2020.Then i decided to cancel the same but unfortunately Go Air airlines told that the amount will not be refunded,it has been reserve into credit shell of the PNR-WDPF3X. But on 26-OCT-2020 I got received an email from go air airlines that your booking has been confirmed with the same PNR on 08-MAR-2021 without given any intimation total cost of Rs-2832 instead of Rs-4671 which had been booked on 21-MAY-2020. I want to go for the legal steps against this fraud.Its not a right way to adjust the fare amount. If they told that there is no refund policy but if they given the option the PNR will reserve in credit shell when you travel you can utilized the same without any extra cost. But they didnt do that. Please help me out ,I want to take legal steps against this fraud. Thanks & regards Sudip Banerjee