Punjab National Bank [PNB] — refund is stuck somewhere within bank's channels

Address:

1018, Estancia tower 1, Guduvanchery, Chennai, Tamil Nadu, 603203

I have not yet received the refund of ₹463 from zomato (Razorpay is the gateway) that was initiated on 15 sep 2019. They've provided me with a refund reference number i. E 30004692599258221546177 and asked me to dispute the transaction as "refund not processed". But the pnb customer care guys are saying there is nothing like charge dispute and they can only check if it has been credited or not. My acc no. Is [protected].