nighthawk c7100v

yeah, checked all the normal stuff, splitters, cables, etc.. I'm in a rental home, moved in 1 month ago, Comcast came out did their thing then left. first check after they left I was getting all 8 upstreams locked. couple / few days later I was running on only 1 channel. researched issues common to " upstream / bonding ", found that Ideally signal strength was 38-48 Dbmv... if signal went too high ( mine showing 57 ) then bond locking can have problems. my old netgear 300 had a option in advance setting to toggle power request to comcast. do not see that option on my nighthawk, do not think a Attenuation problem exist cause I am getting too high of signal / decibals.     as far as Comcast, please, I don't need someone to come out, tell me the line is fine and it's your equiptment, and by the way sense it's you equiptment here is a bill for 75.00  hahaha. not funny. HOPEFULLY, big hope, I can get a tier II tech that has admin rights and can do more than read from a manual