Sendmygift.com – Order not fulfilled and payment not yet returned

I ordered from site sendmygift.com and asked them to deliver this order on 13th feb before 12:30pm as i has planed something as order includes cake and candles but i did not received that order before 12:30pm so i asked sendmygift customer agent to change shiping address but the refused and after that i asked them to cancel my order and refund my money but den also they refused plz tell me what should i do to get back my money? And my order id is 145047999