Myntra.com — wrong item received

I have ordered Louis Philippe Sport Trouser on 29th June 2019 and my order number is:[protected]-4500901 which i have received on 3rd July 2019. The size i have ordered is not fit for me and then i called to myntra customer care for return of my product but according to them i cant return my product as i have collected insider points which was collected my be by mistake. I have requested them to take back insider points which i have collected and return my product which is of no use for me due to size issue.
Is this the way myntra do to customers? If they can return my product then why they are not taking back and refund my amount.
Requested you to help me for the same