HDFC Bank — Refund not Credited

I have returned the product and Myntra informed me that the amount is credited to my account but it is not reflecting in my HDFC bank account. I did a traction of Rs 6400 where I bought 2 products, The other amount Rs 3521 has been credited but the pending Rs 2879 is still not recieved.

Here are few details which could be helpful.

1. Payment was done through UPI with reference number:[protected]
2. Date of transaction- November 16, 10:36 PM
Amount: Rs 6400.50
3.Date of refund processed by merchant : 22-Nov-2020
Amount: Rs 2879 (dint receive till now)
4. Refund was processed by UPI which was the original payment method with reference number:[protected]
5. Screenshot attached by the Myntra( Merchant Query)

Where my bank says " We checked our records and confirmed that the said transaction with reference number[protected] has been credited to your bank account for Rs. 3, 521.50 on November 23, 2020" and the other pending amount is not received by bank from Myntra Merchant bank.

Please help me with the issue.