Delhi University — Payment deducted for Transcript but the website says payment failed

Address:

Delhi

Rupees 1100 was deducted via UPI payment but the online form says the payment failed. At first, I thought it is a genuine payment failure and the amount will be refunded within 2-3 working days. However this was not the case, it has been 6 days now and no refund has been processed.
I contacted the bank and they said the payment is made successfully. (Reply email from bank attached).
I also tried contacting the customer support of DU but they never pick up calls!!
I have a receipt from Paytm for successful payment of rupees 1100 to DU Certificates for the same transaction (Screenshot attached).
Please refund the amount ASAP!