Freakins India - Charged twice for exchanged

I would like to file a formal complaint against Freakins (online clothing brand) regarding unfair trade practice and wrongful charging during product exchange.
I had placed an order under a BOGO (Buy One Get One) sale and paid prepaid. Due to size/exchange issues, I returned the products as per their exchange policy. The return pickups were completed successfully.
However, during the exchange process, I was asked to pay the amount again through Cash on Delivery (COD), even though the original payment had already been made. The exchange should have been free of additional charges as per standard policy.
This issue has occurred for three jeans products, where:
The returned items were picked up by the company.
During exchange delivery, COD was applied.
This effectively forces me to pay twice for the same products.
Additionally, I have not received any proper response to my concerns raised through their chat support.
This act amounts to:
Double charging
Unfair business practice
Lack of customer grievance resolution
I request the concerned authority to:
Direct the company to immediately process the refund for the wrongly charged amounts.
Take necessary action to prevent such practices in the future.
Ensure proper response from the company regarding my order details.
I am ready to provide order IDs, payment proof, and screenshots as supporting documents.
Kindly treat this matter as urgent.