TV issues

For some time now I have been having TV issue......freezing, repeating, blacking out. When I try to use the guide, I get error messages that there is a connection issue, check that connections are secure (they are). Yesterday, technician came out. Did his testing, changed modem and TV box. Now things are worse. This morning, TV started with a greatly enlarged display; couldn't get to settings to look at them. Turned TV off , xfinity menu came up but I didn't change anything and display became norma;l. TV began freezing, repeating, blacking out. Have un- and replugged modem 3 times and TV box once. Working for about 10 minutes. Channel 3 was freezing; went to channel 30; worked for about 15 minutes; started freezing. Through all of this the error code has been RDK03117. Right now modem is a stead white light,. Internet and phone not affected right now but this is not always the case. Tech had left a card with his name and phone number. Called, left message, waiting. I've been keeping a log of issues since Igot Xfinity 6 years ago. I'm soon going to have to start another notebook. I'm disgusted.