MakeMyTrip India — Unable to change old phone number to new

When changing the phone number - the website sends an OTP to the old phone. I do not have the number as it is recycled already. There is no way I can get an OTP on the old phone so I am stuck as I cannot add my new phone number.

I called customer care but they are only able to help with reservations, not provide any technical support. Can someone please help me?