Significant speed drops - only getting 6% of the bandwidth I pay for

My speeds have dropped significantly all throughout the day over the past week.

What I pay for:

50Mbps down, 10Mpbs up

What Comcast's own tool shows I'm getting (http://speedtest.comcast.net/)

3.22 Mbps down, 6.38 Mpbs up

I've followed the usual scripted steps Comcast support recommends:

* Power cycled the modem

* Reseated the cables

* Reset the modem

I see these lower speeds both during the daytime and at night, MTWRFSS regardless of whether I'm

* Connected via ethernet directly to the modem

* Connected via Wifi to a router

Please for the love of god(s) don't make me call into the support center. I spent several hours over the past year working with Comcast support over the phone.

Failing that, please adjust my bill since I'm only getting 6% of what I'm paying for.