Slow speeds and no Comcast callback

I was having issues and Comcast said they needed to replace my gateway. They did that a couple of weeks ago and now I am not even getting 1/2 the speeds I am paying for.  I have tried to schedule a callback with Comcast mutliple times, get a committed callback time and nobody ever calls.

I am paying for 200M with the boost...and I am getting between 28.8-92.3M.