Comcast / Xfinity. Have been forced to use their services for years until a viable alternative arrived in my neighborhood, paid $110 a month for internet to be down at least 2 days a month when my wife and I both work from home. All calls and tickets and emails were met with "you're not using out router and we don't see issues on our side, sounds like a you problem".

Almost left for ancient Century Link pipe when internet was out for 17 hours one day, called 3 times and finally got a competent person on the line not saying the above. Instead said they had done maintenance in my neighborhood and when they sent someone out to look at the uplink it was magically working again. Filed for a service refund thing since it was way below the promised availability and I had to reschedule meetings because my hotspot was slow and they gave me a $1.35 refund to my $110 bill that month.