Putrid customer service

I bought a bed last week for my special needs son, and after sleeping on it one night, I wanted to return it for a refund as it was not what I experienced in the showroom and as per the NCA it is my right as a customer to do so. I was told frankly 'no its not going to happen\ and after much back and forth they would swop the mattress for an upgrade and Id have to fork out the difference. I don't even want to go into the detail of my complaint as it gets messy and ugly. All I can say is the attitude from Matt the area manager and the Warehouse Manager