Paytm Travel - Cancellation fee deducted despite airline refunding full amount to paytm

I booked a round trip for my father from Delhi to coimbatore through paytm travel. Spice jet later sent a mail stating that incoming flight had been cancelled due to a schedule change and that thay have refunded the full booking amount to paytm. Paytm refunded Rs **** back to me out of Rs **** I had paid to them. They deducted the cashback Rs *** and convenience fee Rs *** which I agreed to. In addition they also deducted Rs *** as airline cancellation charge. When I raised this as a concern, they started asking for time to investigate. The complaint was raised in Feb ****. I provided them all proof as asked and in the end they sent an email asking me to provide my bank details to do a further refund of Rs *** via neft. Even though the amount was still incorrect, I sent them by bank details post which they vanished again. They have now started sending the same response of Rs **** being correct and are not answering as to why they deducted the airline cancellation charge for a booking that was cancelled by the airline. Their last response was yesterday where they said they do not operate the airline and the airline has deducted the money. I sent them the email from spice jet again where they have clearly mentioned that the amount was deducted by paytm. I checked on open complaints on paytm in Facebook and a lot of users have mentioned that paytm pockets the money despite airline giving full refund. I have had ** plus contacts with the company but no one is helping and they are saying the amount is correct even after I gave them proof of them agreeing to a further refund. Their telephone team agreed that the refund is incorrect but they said backend team will respond. Whilst the disputed amount is less, as a customer I feel cheated and feel that paytm as a company is cheating and duping customers.