C7000 Not Working Correctly

Model C7000  never updated firmware and used on TWC but when tried on COX I was told: 

The problem we experienced was that the modem appeared to be in a loop never being able to connect  to the Internet.  When it was turned on or re-started the first two lights near the top would come on in sequence the next light, the Internet connection would never come on steady and the sequence would go on and on. 

I have had COX checking my network connection as the router was not accessing the network and was continually rebooting itself. The technician who was just here said the router had issues and should be returned. My old router is working fine but I was really wanting to obtain a dual band router. He did confirm that this router was supported by COX and that this was not the first of these that had problems -- apparently when they work they are great..

Any help would be appreciated.

Can I have someone look at/repair this?  Do some of them just go bad?