Lies about Delivery timeline s

I purchased my mattress online and I was specific to choose a product where I can get quick delivery I was told the product would be delivered in 3 business days. On Friday I received an acknowledgement of my order and I was informed on 100 day policy thing which I had seen when I made my purchase but decided I do not need. Monday I was once again told my order and payment was received. It's almost 7 business days now I am being given an order update that my order has been placed and I will be advised soonest when the product is ready for delivery which means that delivery will not be happening this week. When you place your order their system tells you whether they have the product in stock or not. I made my selection based on that. Their warehouse is literally 10 mins from my house but because of work commitment and their promises on the website I figured online will be just as quick. Not so. I would actually want to cancel my order and go purchase somewhere else at this point if I cannot receive delivery in this week.