Internet Keeps Going Down

For the past week, my internet connection has been down constantly. It will be on for a minute or two and then it is down again. I have tried unplugging the power on my modem and router, then plugging it back in, which brings the internet connection back for two minutes tops before going down again. My modem, router, coax cables, and splitter are all only a year old. I need internet for work and am at my wit's end. This has been constant all week long and Xfinity refuses to allow me to report an outage. Then I will get a text the next morning saying an outage has been detected in the area, they are fixing it, then its "fixed" and my internet works great again for maybe 3-5 hours before its doing the same thing again. I have an appointment for tomorrow (which was cancelled and rescheduled three times now) but I need to have internet. I haven't been able to work all week and Xfinity doesn't even have the decency to give a credit for my internet being down all week. I pay way too much money for this inconsistent service to be acceptable, and this is the only time in the year I've had service that I've had this issue.