mini box keeps loosing guide

We have 3 of these boxes and occasionally they all loose the guide but not very often, except for one of them and it has gotten where it loses the guide almost every day. Sometimes it will not even bring the guide up. We have unplugged it and left if from a minute to 15 minutes or more. We have reset the connection from the COX website and/or just unplugged the main DVR. We checked and wiggled connections. Tried having it test itself, most times it says cannot connect but will sometimes and has updated itself when it did connect. We have run a channel scan.  All of this has been done on a daily basis the past few days. We can fight with it for several hours and it finally comes back, not sure what fix actually worked on it. I am thinking this box is bad? How do we go about getting a new box, or should we try buying a new cable first?