Myntra.com — H&M leather Slides

I ordered H&M slides but on delivery date the delivery agent said he forget my parcel at store. And day after that my order got cancelled. I tried to order the product again but it went out of stock and prices raised more than 60%. This is so unfair.
I have tried every possible way to explain the situation to myntra executives but they said i have to deal with this.
Myntra should work on this and should provide the customers their order at the same rate on which they have ordered. Otherwise this could be a scam also. Myntra from their end reducing the price and after payment processing they are not delivering the product. And for so may days they are keeping the money with themselves and rotating in in market so ear interest.