Internet is getting disconnected again and again

First. Please try starting here if you wish;

https://forums.xfinity.com/conversations/your-home-network/connection-troubleshooting-tips/602da777c5375f08cdea3db9 

Hey there, @user_b2x2w7! Thanks for creating this post. I'm sorry to hear about the trouble you've had with your service, and I'd love to see how we can help! It appears our Expert shared some connection troubleshooting tips with you earlier. What steps have you taken so far?