Wine Fridge Repair

I have one of [these](http://www.silhouetteappliances.com/us/products/dwc518bls-us/) (or thereabouts - it's older, but looks like this one) that I inherited from an old roommate. The temperature gauge for the lower section seems to be out of whack. It's very cold inside, but the display reads ~78°, so it never turns off.

How difficult would it be to fix something like this? Or, what should I look for to find someone who can repair it?