Indian Bank — Refund initiated by flipkart still not received in bank

My name is Arindam Banerjee, I bought a mobile phone for ₹18, 999 in Flipkart through my brother Arnab Banerjee's Indian bank debit card. Then I returned the phone to Flipkart. Flipkart said that I will get my refund within 31 December 2021, but to the date, I didn't receive my refund, so I contacted Flipkart customer care. They told me that they have completed the refund on 25 December 2021 and the same should have been credited to my account by December 31, 2021. And gave me a Payment reference number- PZT[protected]VZVHF02, and suggested me to call the Indian bank helpline number. I called the helpline number but No one picked the call. Please help me to get my refund
bank account no- [protected]
IFSC- IDIB000G555