Punjab National Bank [PNB] — Regarding my refund from air india

Address:

PNB RATGAL BRANCH,KURUKSHETRA,HARYANA,INDIA

I cancelled air india ticket on 14 oct 2020 and they told me that my refund of rs 51500/- has been initiated on 20 nov 2020.but till date i havent got my refund in my bank account.Air india has also given me a transaction reference no: 098BK143959ZC.i contacted the bank and they told me that we can do nothing.what should i do now.