Air India Express — Refund pending since last 17 month

I have booked 1 ticket with PNR no. HXUBVF. The flight was cancelled and I am waiting for refund since last 17 month. So many email sent to Customer Support, Nodal Officer of Air India Express but not got my refund. The company is full of inefficient and corrupt staff, so if you want to book your ticket considering it as non refundable even if clause says refundable. On cancellation they are not going to respond at all.