At some point I think it can be considered legally misleading to have things included that are not showing on the Website, despite any disclaimers about errors. I know there have been cases in small claims court that will uphold a financial loss due to errors relied on from a website.
That would mean, if you want to terminate your contract with no financial loss, there is a probablility you would be allowed to in Court. Otherwise, if you are keeping the service, Dish would probably prevail, as you are not at a loss. (The remedy in Court would be to terminate the contract - not to make Dish provide those channels)