Cheated by online shopping

I have ordered a dress material on 13th August In as I found 100% Cash back offer.It is a Combined order along with this product amounts Rs.800.The Shopclues announced 100% Cashback on Placing Orders above Rs.690 But for Selected Products.They announced the offer is Valid from 11-15th August.Suddenly I Could See My order was cancelled. My order Number is 64986857.After few days they sent me a text that 'the Dress material was not in Stock and so we are going to Cancel the order'.I understood their Situation and Fainted my dream to get 100% Cashback. Second time I have ordered another Combo of dress material[Quantity 2] for Rs.1000{order no 65716291}.After Five days my order was cancelled. I have already made payment for this product.I have Called upon the Customer Support and asked them why my Order was Cancelled.they are describing the Same there is no Stock of that Product which I have Ordered.When I placed my Order it showed that the product was in stock.then how Can they Say the Same. advertises One Day Deal and making unbelievable discounts on products.When we try to buy that product,they say Prepaid option is only available to order that Product.When We Place Our Order,After few Days,We Can See the product will be Cancelled and they Would Describe that product was not in Stock and We are Going to Refund Your Money Within 4-5 Days.They are Cancelling the Order after 3 processing days.In all those processing days saying Procurement Delay From Merchant.If there is no stock they Can it Within a Day.But they are not doing that.Simply,Shopclues tries to attract the Customer's Money and Releases after 8-10 Days. This Shows that my money is used for their Purpose and then they are Cancelling the orders.. Can I File a Complaint Against them?