Indian Oil Corporation [IOC] — refill booking cancelled but my amount paid was not refunded.

I booked a lpg on december 27, 2019 and paid for it on the same day through online using my hdfc debit card. I also received a confirmation for my payment. Invoice for my booking was created on december 30, 2019 and on december 31, 2019, i received a message that my booking was cancelled due to price change. The booking is cancelled but the amount i paid for my lpg was not refunded. Need your assistance as soon as possible.