Did not deliver the order even though the product was in stock

I ordered Xiaomi power bank 10400 mAh (product was in Stock) on September 1 2014 and the delivery date given by flipkart was 8th September 2014 (product was shipped on 1st itself and prived the tracking code), but they failed to deliver. Then I made calls to flipkart customer help desk, they said there would follow up with the courier service and promised that they will deliver the product by max to max 12th September. But again they could not keep the promise they have made and they failed to deliver the product by 12th. After that I further called the customer care, and talked with the supervisor named “Asha Panda”, she said would look up the issue and deliver the product by 16th of September. But yesterday morning (on 13th September) suddenly I got a call from flipkart cutomer care and they said that product went out of stock, the product cannot be delivered. I asked them what is the problem with the order, they did not answer and said we cannot deliver the product which was on the way. The flipkart has been harrassing me since 2nd of 8th of September, everytime they promised but they failed. So I want to file a complaint against them.Please take serious actions and help me to get my order.