Myntra and H M - Refund not received

I ordered a H&M joggers from Myntra on ** December and it got delivered on **, but since the quality was not satisfactory, I applied for a refund. It showed that if I chose UPI as the medium of refund, I'll get my refund within a day of procession of the refund. The refund was processed on **th and it showed I'll get it by **th but I still haven't got it even though it shows my refund was done instantly. I contacted their customer service yesterday and I was told that it will take *-** days even though UPI transfers are done within a day as per their own policy. This is happening for the second time, I ordered a denim jacket in January, I paid ₹**** and I still haven't received the refund, I checked my bank statement several times but I still haven't got it.