Knocking Noise coming from Refrigerator

I purchased this refrigerator (model CP171SS) through a Lowes store about 8 months ago. I had a very narrow space in my kitchen for a refrigerator and this seemed to be a perfect fit. After owning the refrigerator for approximately 4 months, the refrigerator started to make a knocking noise every hour or so. At first it was not that noticeable, but over time the knocking became louder and started occurring every 15 to 20 minutes.
I contacted Summit Appliances several times and received no response to my request of having the refrigerator checked out by a service technician. Finally after over a month I was contacted by the local technician and the unit was checked out. Unfortunately for my sanity the service tech said that there was nothing they could do to remedy the problem.