Internet speed lagging far behind plan's promised speed

My internet is far behind my plans 800 megabit promised speed and has been extremely choppy in service at that. Sometimes it can maintain 100-200 megabit speed but then quickly jumps down to 1-4 megabit speed. I attempted to use the automatic (rather useless) robot agent thing and it provided nothing of use besides treating me like a person who has no technological know-how. This issue has been happening since Friday (3/7) and I need this issue fixed and really I should be demanding some sort of compensation. If I pay for the service, it should work appropriately

. I have been a loyal customer for many years but the lack of customer service and aid is truly appalling.

Yes I have tried my connection on multiple devices, yes I've restarted my router plenty, the issue does not lie with user error but Xfinity's service.

Attached are some screenshots of the internet speed throughout the day.