Here is a suggestion....
first go behind the wet bay panel where you connections are for you sat input, cable input, etc. Note the color of the cables. At least I think they are different colors. Make note of the color of the cable coax and the satellite cable.
Then pull out the antenna/cable switch box. The 3 ports on the back of the wall plate are labeled 'Cable", "Antenna", "2nd TV". You want the cable coax from the wet bay plugged into the "Cable" input. You want the antenna cable (this one is a guess) plugged into "Antenna" and the remaining cable is what goes to the bedroom and main TV (this is the cable that has a splitter somewhere in the rig that feed the bedroom and main TV.
Most likely Spectrum took the cable input and connected it directly to their cable box which then fed (via HDMI?) to you main TV.
Lots of photos and a diagram of your current wiring would be helpful to troubleshoot this on line.
finally - NEVER let a cable provider tech inside your RV. It is just an open invitation for a disaster. I follow them around when back home correcting all the messes the make so folks can use Spectrum, cable, air and satellite when on the road.