Myntra.com — Harassed By Myntra,Plz Advise

Address:

West Bengal

I Ordered a DC Comics T-Shirt,Along with Some Other items To Waive The Shipping Fee.

3 Hours later I check Back,My order Has been cancelled,The Cost Of the T-Shirt Has Been Credited as Myntra Credits and The Discounted amount I Got Back as Coupon.The fun Started Now.The Coupon Cant Be used on Discounted Items,But all the T-Shirts I wanted to buy were Discounted.So i Couldn’t use the coupon Now. plus,I cant buy The T Shirt Only Now Without paying the shipping Charge.
So basically a Mistake That Myntra Made,I am being harassed.
Talk To the CC revealed that its a System generated Mistake so therefore They cant do anything.What BS!!!
Please Advise what to do

TIA