My Flower Gift — Not delivered item and asked extra money as delivery charges.

Before ordering cake and flowers for my parents wedding anniversary I have confirmed with customer service 3 times that they will deliver it on that day. After placing order even I didn’t get a confirmation mail. No response from the person I chatted before placing order and they have not delivered the item. Next day they mailed me asking for additional 400 rupees as delivery charges which was not there when I placed order. When I asked to cancel the order and refund the amount, they refused. They have taken my money and spoiled my week.