All Internet Tier Speeds Are Slow

I have the Gigabit speed and I have had problems since last month.  All power levels are good but my max speed was only 475 down and 42 up.  This morning it's even worse.  Now my download speed is 10 and upload is 11.  What is going on with you guys at Comcast.  If this is not resolve by the end of the week I'm switching to AT&T.  Their Gigabit speed is half of what I'm paying now with Comcast.  If you guys don't get your act together a lot of your customers will be moving to another company that can provide them with the service plan they are paying for.