Amazon India — I didn't received my refund

My self Sandip Sengupta, i ordered a product (Sweeping robot- Mixen Intelligent Automatic Sweeping Household USB Rechargeable Robot vacuum cleaner worth Rs. 3, 499/-) from amazon on 25th November 2020. But my product was defected so I returned that on 2nd december 2020 to amazon. I claimed for refund to amazon so amazon send me a message for initiating refund that they had initiated my refund on 3rd December 2020 at 08:01 Am, but yet I didn't get any message from my bank that for any transaction for Rs. 3, 499/- I called to amazon and they provide me a reference no. "[protected]" for my transaction. I called to my bank "union bank of India" they said there is no transaction on that date after that again I called to amazon and discussed with this problem they advised to file charge dispute, (Reference no. "[protected]") so I want to do charge dispute file. My amount is Rs. 3, 499/- and name - Sandip Sengupta,
Mobile no. [[protected]] my account no. Is [[protected]] ifsc code - ubin0534994.
Please help me to credit my refund Rs. 3, 499/- in my account. Please file charge dispute. Kindly help.
I am enclosing here mail image which is recieved from amazon.