Flight Canceled Due To Airline Change, MMT Denied Full Refund

I booked an international Etihad Airways ticket via Makemytrip (MMT) in India. The airline later changed the schedule significantly, and Etihad confirmed multiple times that my ticket was eligible for a full refund. However, MMT kept insisting they needed written confirmation from the airline. Etihad clearly stated that MMT is aware of the policy and no written confirmation is required. After repeated follow-ups, MMT finally confirmed on a recorded call that they got verbal confirmation and would process a full refund. Now, I’ve received an email from MMT saying I’ll get zero refund. I’ve contacted both MMT and Etihad over 100 times without resolution. The ticket cost me ₹66,000, and despite eligibility and compliance on my part, I’ve been denied my refund. This seems like negligence and miscommunication between the airline and OTA. I want to know my legal rights, whether I can raise a chargeback through my Indian credit card, and what it might cost to pursue this legally.