Frequent drops at my gateway. Possible solutions?

I've had AT&T U-Verse internet for a couple years now and have to say that I would currently rate our experience at about 7/10.  The reason I give it a 7 out of 10 is because I had to spend $179 on a new router to supplement the lackluster wireless capabilities of the provided gateway (NVG510).  I purchased a NETGEAR Nighthawk AC1900 and my wireless performance has gone through the roof!  Well, the one thing the new router couldn't resolve is the frequent drops in connection at the gateway.  I'm not sure if this is a problem with the gateway, connection, service, etc., but the problem never seems to go away.  

All that being said, what are my options to resolve this issue?  I've had a service technician come out before and it only fixed the problem temporarily (a week maybe).  Has anyone else had similar issues with their service?  If so, how did you resolve the issue?  I'm willing to try anything to get this fixed because it's extremely annoying.