Ping Spikes and dropped packets

do you have a screen snip of the cable connections page and event logs? 

that helps us check the connection back to the isp. 

they're great at saying "its not our line". 

And it might not be. 

Check you coax line for kinks, bad/old/loose connectors, moisture in the line, etc. 

Also, if you have any splitters, amplifiers, or attenuators, remove them from the line. preferable, directly connect the c7000 to where the coax comes into the home to prevent the wiring in the home from being the issue.