Myntra.com — did not refund full amount

Address:	Gandhinagar, Gujarat, 382009
Website:	myntra

Hi
I am facing problem with refund from myntra.
I had earned myntra points by donating my things that i used for shopping.
On returning 3 items (Not satisfying as per description details), myntra didnot refund full amount.
I called them up and they said they have deducted amount for donation.
I gave donation materials also and my money also got deducted.
Amount due - rs 308
Please help.