Air India Express — delayed flight compensation

My flight from mumbai to doha was delayed for over 8 hours. I had to get a new flight as i was only in doha for a short time. I was promised a refund and received nothing. My flight was ix243 on the 1st november 2018 my pnr reference is aipaaq. I was sent emails and texts informing me of the delays with no reason why. I was stuck at mumbai airport hungry and tired and wasn’t allowed to be issued a boarding pass to enter the main airport to eat. It was 6am and the only option was burger king which was closed