I'm having the same issues as the post noted below:

https://forums.xfinity.com/conversations/customer-service/maintenance-crew-wont-fix-the-main-line-to-my-neighborhood/66a9710359bf556396a16384

I have had 3 technicians come to my house. Great techs who have tried hard, but my issues have yet to be resolved. It has been going on about 2-3 months and I no longer believe it has anything to do with my house. At times, as described in the link above my internet is completely unusable. My tv and online devices freeze due to intermittent internet issues. I also am unable to game because of high latency spikes and packet loss.  Prior to this 2-3 month time period, my internet worked completely fine. It's important to note that it's not as bad earlier in the day, but as the network gets more congested from 6-11pm my issue gets a lot worse. This is on top of me paying 150 dollars per month for internet that doesn't work which is unacceptable. I've added a screenshot from my speedtest which shows the variation in speed. This is a speedtest connected to the Comcast Sacramento, CA test server where I am currently located. This has also been done with a wired connection from the modem to my computer using ethernet with the same results. At this point I believe it is a damaged line or node that services my neighborhood which they have yet to check. Please help me to resolve this issue as it's leaving a really bad taste in my mouth regarding Xfinity. I just don’t understand is why the techs have not tested the line coming into the neighborhood etc. 

Fixes that were tried:
Changing the xb8 modem (Did not work)
Buying my own modem (Did not work)
Disconnecting my router and removing the xb8 from bridge mode (Did not work)
Xfinity changing the line from their box to my house (Did not work)
Xfinity changing the fittings on the cable line that comes into the room where my modem is (Did not work)
Xfinity Removing the splitter that supplies coax to all other rooms that use coax, leaving one connection. (Did not work)



Internet issues.