Intermittent Connection up to 80 disconnects a day

Hi everyone, 

This is my first post in the forum, and I need your help. I have been an Xfinity customer for 10 months now, and from day 1, I had an intermittent connection. We had countless chats with customer service, technician visits from Xfinity and ComCast, multiple modem replacements, and renewed every cable, including the one from the ComCast box to the apartment. 

Every day, around 8 to 8:30 AM EST, the internet goes out every 4-5 minutes for 3 to 60 seconds at a time. This happens all day until 6-7 PM. It disconnects from 15 to 80 times a day. I have a PC connected to LAN; other devices are on Wi-Fi. The modem is a brand new Xfinity xFi. The last Xfinity technician tried a few things and was hopeless at the end. 

I monitor the connection using a Chrome extension, and when the internet goes out even for 60 seconds, the modem's LED light stays solid white. 

When the technicians updated the cable or the modem, things were fine for a day. Then, the pattern would start again. Is there anyone who has experienced anything similar? Any advice would be greatly appreciated!