Myntra - Myntra account balance reduced to below Rs 700 from above Rs 2000 they say money expires if unused e

I had Myntra balance above Rs **** ( cannot remember the exact amount) till dec **. Now the balance is below Rs ***. On complaining to Myntra they are saying it’s their policy that balance amount expires after a certain time. If they are running their company by sweeping out money from their customers accounts without specific intimation, they are indulging in fraud. Daily they are sending millions of mailers for promotion but they do not think it’s important to inform customers before deducting cash from their accounts. I want to get my money back as I have paid for it while purchasing the products and it was the refund lying in my Myntra account which they simply cannot just sweep out in the name of their policy. What kind of policy is this which allows them to steal their own customers money without selling products ??