Internet has constant drops daily since early 00's. HELP!

Since we've had the internet in this house, we have had nothing but connection issues. We have had every modem Xfinity has offered. We have had a parade of techs come to the house. They change the modem, the rename my network incorrectly. Multiple techs have gone out to their trucks to get a "new" modem, just for it not to even work during the install. We have had new lines run from outside to our house. We have had new coax lines ran inside the house. Every tech comes, cuts off the ends of the coax, replaces the tips, swaps out a modem and tells me everything is fine. And then hours later, we continue to have these very quick drops of service. Now this is impacting my job. I work from home and don't have an office to go into. I need the service I am, and have been paying for. I can't EVER get a supervisor on the phone, and trying to get someone to come to the house is impossible. I would love to show the mess of wires to the supervisor from years of hackjob work done. I have tried everything I can think of. Every time xfinity comes out, they brush us off and say, "we see the signal at your house so you have service, there's nothing we can do." I am to the point of reaching out to the BBB, FCC, and states attorney. Why does it have to go to this point? Why is NO ONE able to figure this out?