Trade in

I have a MacBook Air (13-inch, Early 2014) that I had recently purchased from Walmart as refurbished...is there any way that I could trade this in for a newer one. It is not working how I thought it would. My messages from my phone don't go through to my computer, it won't let me download apps due to it saying that I need to update my computer but it is saying there are no new updates available.