adani one app - Flight tickets rescheduled to random future dates and no refund provided

I booked a flight from Adani one app with PNR *DRTC* of Thai Viet jet airlines. It was two way flight from Mumbai to Phuket departing on *rd may **** and returning on **th may ****. The airlines rescheduled the departing flight to **th may **** and return flight to *st june ****. When I requested for refund from airlines the airlines refused and asked me to contact the agent because the booking was done via Global Distribution System. Adani one customer support refused the refund saying it is not possible to refund unless the airline refunds. As such both parties are refusing refund for the service not provided. The screenshots of correspondence are attached herewith.