Hopes were high when India's biggest online retailer, Flipkart, announced a day of massive discounts – but it didn't go exactly to plan, writes the BBC's Shilpa Kannan in Delhi. Logging on at 07:58 on my tablet, I was hoping to buy mobile phones at 1 rupee ($0.02; £0.01). Along with me, were hundreds of thousands of other online shoppers across India. This was supposed to be India's version of Black Friday – the start of the Christmas shopping…