Refund money is not getting paid back

I ordered the “Strapless Butt Lifting Bodysuit” (Order Id : 495428) from this brand called “underneat” however due to size issue, i raised an exchange request and there goes the chaos. First of all, nobody came to pick up the item for a month, then after picking, i was continuously following up to provide the exchange item but their team emailed me that the exchange will be delivered soon in 7-8 days which eventually never happened. Instead, later on one of my emails, they apologised for the delay and the same cycle went by again stating that they will deliver the exchanged item soon. Eventually it never happened and out of frustration, i asked to initiate a refund for which i sent email again and they agreed to initiate the refund but refund never happened. Again they apologised for delay and asked me to share my bank details but refund never happened and now they are not replying to my emails!!