RDK 03005

I just upgraded to the x1 DVR service. Self installed the box a week ago and it worked perfectly that day. The next day I turned it on and got an error code RDK 03005. Tried restarting on my own several times and then called customer service. They ran multiple checks, transferred me to repairs, who transferred me to a technician. Tech came the next day, gave me a new DVR box and added some "filters" or something to the cables. Worked fine. Next day got the error message again...called again, tech came, new box, etc. etc. Have now called about this 3 times and have appt scheduled for the third technician today. No one seems to know how to fix this issue - each time the TV is turned off for an extended period the RDK message comes up. Sometimes when on the phone with customer service they can successfully reboot, other times they cannot. They seem to think the signal going to the box is fine, but the box is having issues connecting to the internet. When I check online it shows that my main TV box is offline, and also shows that I have more than one device but I only have one TV and TV box. Wondering if the cable modem/router could be the problem, but customer service seems to think it is compatible. So frustrating...does anyone have experience with this??