Internet Clearly Being Throttled

During the quarantine, my internet has been consistently at 5-7-mbps.  No ups or downs at all.  When I unplug my system it begins where it used to be at above 30mbps and even much higher.  But within 5 minutes it is back down to 5mbps.  This isn't a coincidence.  I used the "speed test" on Xfinity's website which showed me getting above 40 mbps.  That's BS.  I used 3 other testing services on multiple devices and all of them confirmed my speed to be around 5mbps.  I am barely able to browse webpages or load a video.  

With 4 people working from home, needing internet more than ever, this is not cool.  Since I am being throttled to 10% of the speed I am paying for, can I pay for 10% of my bill?