Missing Part-Durabrand 5 Speed Blender

I purchased a Durabrand 5 Speed Blender from the johnstown Wal-Mart and unfortunately I let my 2 year old sons play with the receipt. When I got home and went to take the blender out of the box, (two days later), I found that the container was missing. I went back to the store with the base still in the packaging, and they told me that more or less I was lying and had just left the container at home and was trying to get another container. This is far from the truth. THERE WAS NO CONTAINER IN THE BOX WHEN IT WAS OPENED AT HOME. I do not want to have to purchase another one all together, as they will not even give me a refund. Please help as I really like the Durabrand brand as it is a great value for the money, especially for someone like me with twin sons and being disabled. This brand has lasted me quite a while on other products and I really do not want to spend more money for the same thing with another name on it. Please help me.