Intermittent internet

Like multiple posts before me, my Internet connection drops out 3-12 times per day for 5-20 minutes. It restores itself. This has been going on for 3 months. 

I have had at least 10 chats, 4 phone calls and three service calls to my house. On the second call the underground cable was replaced. Then on the third call a maintence teck did something down the street. Don't know what was done because they left without telling me. 

None of he other similar posts had any kind of a response. Maybe someday Xfinity/Comcast will be able to figure this out and fix this. If anyone who reads this has a remedy, please advise. 

Thanks