Sorry for the problems you are having with the On Demand. I have looked in the On Demand folder and have compared the 4 items in there to the episode list of Dallas and see the last 4 episodes are currently watchable for free. Please let me know if you are in still need of assistance.
I am having an identical problem. I have spent 3 hours in online chats getting shuffled back and forth between customer service, billing, and tech support. With several channels that I subscribe to (we'll use TNT as an example), in order to watch an episode on demand (for example, the most recent on demand episode of Rizzoli and Isles), a charge of $1.99 or $2.99 is listed, despite my online on demand guide noting that they are free, TV only, video on demand episodes. I want to watch them, but will not pay an extra charge for a channel I already subscribe to. What is the solution to this ?? Someone tried a remote STB reset that had no effect.