Flipkart — Cancellation Charge incorrectly

I have cancelled a flight booked through Flipkart. From the airlines, they have refunded full amount but since I have booked through Flipkart, they have deducted cancellation charges of Rs 400 and the convenience charge of Rs 299. I understand about the convenience charge deduction as it was mentioned in the cancellation policy documents. Now my complaint is that in the Flipkart app where I have booked the ticket and cancelled it, it was written as Rs 164 so based on that I have cancelled it thinking it will be only Rs 164. Now when I complaint to the Flipkart saying that they have mentioned Rs 164 but charged Rs 400, they are saying that it is the process and not agreeing to refund the extra money.
They are cheating the customer with these tricks. it may be a small amount but what they are setting expectation to the customer is very incorrect. The complaint number that I have raised through Flipkart is 16142107.