Punjab National Bank [PNB] — Refund Initiated but not received

Address:

7 Bhikhaiji Cama Place, New Delhi, Delhi, India - 110607

I had a double payment of a product on Amazon, the refund was initiated by Amazon on the same date 01/05/2021 and I haven't got a refund yet. Amazon is saying to check the Refund Reference number which is 30005411221121018955706.
I called PNB Customer care they just asked me for some of my details like address Pincode, account number, DOB, after that they said they can't help me with the use of the refund reference number. I have no idea how I can use this number and track my refund. Amazon customer care also says that they have fully initiated the refund now only the bank will have to provide the refund, and the banks themselves seem clueless about how to use the Refund reference number. Please I need help with how to track my refund and by what time will I receive it.