wifi issues

Any suggestions?  I upgraded to a Panoramic wifi router because I was told by COX that would solve all of our wifi issues.  After upgrading - we are having terrible speed and loss of connectivity happening daily.  A technician came out and there were issues outside.  It worked fine for a week - up to 970 mbps download speeds - now we are back to around 170-300 mbps download speeds and losing connectivity multiple times per day. I've done so many chat sessions and phone calls - I'm ready to start charging COX for my time.  I'm spending HOURS each week trying to deal with this issue and paying COX for gigablast service.  What can be done about this situation?