HDFC Bank — refund not processed

Address:

Mumbai City, Maharashtra, 400050

I have bought an item through myntra app through bhim upi and they have processed the refund and the bank hasn't validated the refund yet thus it is not reflected in my account.
Amount - rs. - 1295.00 - bank reference number is[protected]

This is what they quoted me when i complained-

"dear anuj,
I understand your concern regarding the refund of nike men grey flip-flops.

The refund has been successfully processed into bhim upi on 12 dec, 2019 and the amount should have reflected in your account by 12 dec, 2019.

I request you to get in touch with your bank support team with the following reference number/s and request them to validate the refund transaction/s. The contact details of the bank support team will be printed on the flip side of the debit/credit card issued.

Amount - rs. - 1295.00 - bank reference number is[protected]

Some nationalized banks may take more time than normal to credit the amount. If your bank support team is unable to locate the refund with the reference number provided, please dispute the transaction as 'refund not processed' with them. At that time, they will see a pending refund and will follow the path back to our payment processor to locate the refund."