Problem with cable box and customer service

On Saturday 10/5 - my main cable box stopped responding - couldn't get Guide, change channel, use voice remote - pushing Xfinity button did nothing.  I stupidly followed Xfinity directions to use the Xfinity Assistant.  It is really not programmed for an unusual problem and following it's suggestions made the situation worse. After an hour - I got to text chat with a human.  She was friendly - but made the situation worse by having me un-pair the remote altogether from my LG TV.  Then she disappeared and a new human came to text chat with me.  While waiting - I had taken the remote - which I was being told was the problem - and easily paired it with my other TV with is also LG.  So the problem was clearly the box.  Finally, the second human I texted with agreed that I had troubleshooted enough to merit a technician visit.  A technician came on 10/7 - witnessed the problem and said I definitely needed a new box.  He installed it and set it up with a new remote.  It worked fine that night but this afternoon 10/8 - the same problem recurred.  If I unplug the box - it will work fine for about 1/2 hour then stop.  So - I tried to call Comcast to talk to someone.  The system is now set up so that you are required to go through the Xfinity Assistant.  The voice system will not put you through to a human and actually hangs up on you if you keep asking.  I am at my wit's end.  There is probably something wrong with some connection that goes to this box but I don't know how to get a tech to come to investigate. Disgraceful that it is virtually impossible to speak to a human being at Comcast.