Air India Express — Refund Payment not received

I had cancelled an air ticket on August 8th but still now didn't get the refund. Spoke multiple times with customer service and emailed also to Nodal team but still now no response from either side. Nodal team chief manager Mr Aby George said the refund will be done within in 7 to 10 working days which was on 10 of august but still now I haven't received the payment. PNR NWJCWD. No one is giving exact information and giving the refund also. Need an immediate intervention in this matter as its been more than 18 days that I have cancelled my ticket.