Make My Trip - Unauthorised deduction of amount and generation of ticket without submission of otp

I am sumesh m. I was trying to book a flight ticket in ' make my trip' from guwahati to bangalore today i.e * sep ****. earlier it was showed an amount of Rs ****.** for the aforesaid ticket and I had proceeded with booking. I have entered my card details and I noticed that they have added a convenience fee of rs ***.** which was not shown earlier. however I have no problem with them in adding the convenience fees. but when i had entered my card details and proceeded for the otp page. Simultaneously the otp has been generated before I could see the otp page and the 'otp' has got submitted automatically without my submission and Air Asia flight ticket has been generated. All these happened in no time before I could see the payment gateway to submit the otp. When I have contacted them regarding this issue they responded that it has happened due to my phone's error or my fault and they said that they had no designed system to submit the otp automatically. but I was not ready to admit that. when I have contacted them again they said that i had already given permission to read messages in the mobile application. I wonder that permission was to read messages and not for submission of otp. I have argued with them that 'submission of otp is to be done by the customer only'. but they were not ready to accept my complaint and kept saying that it is not their fault. I have contacted them more than * times and all were not ready to cancel my ticket and refund it. I have also got confirmation from the credit card customer care that it is the mistake of 'make my trip' and I was asked to contact them only. I have kept saying that they (make my trip) can only read messages but otp submission is exclusively to be done by the individual only which is a great security issue. at last they have agreed to give me an amount of rs **** voucher which can be used for further booking with them. I am not satisfied with this and i want them to refund the full amount and cancel the ticket. Atleast they should have the courtesy while dealing with the customers and should not get into defensive mode.
I request you to please look into the matter and do the needful for my refund of the amount and further desist them with 'automatic submission of otp' and this kind of harrassment and experience may never happen to any other customer in future. I am enclosing my ticket and screenshot of call logs in support of the complaint.