Sell products while not having stock

We usually buy from Dail-a-Bed and we are very happy with the service. This time we made the mistake of buying a mattress from Mattress Warehouse and we are extremely unhappy with the service. Not only do they sell products which they don't have stock off, they say 7-10 working days and when we inquired on why we havent recieved it yet, they then tell us they are still waiting for stock. If their website showed "out of stock" we wouldnt have bought it in the first place. So they sell you a mattress which they don't have, take your money and then just don't deliver it. Do NOT buy from Mattress Warehouse especially not online ! We want a full refund immediately and we will rather go buy from Dail-a-Bed instead