ISP issue

Hello, for a while now I’ve been experiencing issues on fridays and saturdays 12pm to 8pm. I know exactly what the issue is; the pizza place located next to us hosts live music every Friday and Saturday and it congests the node. We are surround by companies so I doubt other people complain about it for it to really rise an issue but we live right in the middle of the companies and it is a nightmare. Resetting you modem, restarting devices, even getting a new modem and checking the cord to assure they’re correctly installed; you name it we have tried it. The modem as well as monitoring it on my laptop shows that the internet shows full bars the but actual speed is not there. I’m talking a 15gb game took 2 hours to download. This has been going on for months. I’m convinced fully now that this is an isp issue and we need a node split. When the pizza place isn’t hosting live music it’s fine or when it’s not busy it’s fine but on the busy live music nights it always starts up and the second they leave it instantly goes back to normal, I’ve tried call Xfinity support and I had to explain what a isp issue was to the employee…. So clearly I need someone who knows more than the phone operators. We have been with Xfinity for years and would like to keep it that way but if the issues don’t have a solution we are gonna be forced to change services in a attempt to hopefully have internet on those days and times.