Why aren't ALL my channels in HD? - XFinity

I pay extra money to Comcast for HD service, yet some of the channels I receive are not in HD - channels that I know are available in other parts of the country in HD.

Why are they not available to me when I am paying for them? This is the 21st century. I am being charged for services that are available but I am not receiving.

I want all the channels I receive to be in HD if they are HD capable in other parts of the country or I want to be reimbursed.

And I demand that that reimbursement cover all the years I have been overcharged up to the present.