Started Unicast Maintenance Ranging - No Response received -

I've had internet issues for the past 3 months. I'm getting random disconnects. I've had 3 techs out and they all say there is no issues. The last tech called for a sweep because he thought he saw some noise and I got a note on the door saying levels were adjusted out side. 

I am currently using a Cox gateway and I noticed the error I showing on the router event log. 

My internet disconnects every 15-30 min from 5 secs to 2 min. Some days its fine and other days its horrible. Seems to get worse at night and my cable channels tend to pixel-ate pretty badly at night as well. 

What should I do next?