Disappointing customer service and product

We rented a slush machine last weekend from this company for my son's 6th birthday party. The machine did not arrive with instructions and the driver told my husband what to do to set it up. These instructions proved to be incorrect and the slush machine did not work at the party at all. On contacting the company on the Monday they told us their machine was working just fine, the instructions provided were correct and basically insinuated that the problem was the user rather than the instructions. Additionally, the slush mixture is tasteless and their response to that was "One man's poison is another man's meat". Really disappointed with the whole process as well as the lack of customer service. In these times were there are so many options for service providers, I feel that customers should be treated with some sort of respect. I would never use them again.