Xbox live gaming impossible

[Edited: "Inflammatory"].  They reset my modem and tell me everything is ok but of course it's not. I pay [Edited: "Language"] for fast internet but after 8pm at night it's impossible to play online games.  I have been through 3 modems and 3 routers and the problem they say is on my side.  I am looking for another company to go with.  I have been with Xinfinity for 20 years [Edited: "Inflammatory"].