Hi Pearl60,
Sorry to see you feel this way, I can appreciate the frustration that this has caused.
I've just looked into this further and episode 16, of series 4 is not yet available on our set top boxes.
This would mean that this has not yet been made available from the broadcaster, but we will make this contact available as soon as possible.
Not all On Demand content will be available on the app, this is due to licensing.
David_Bn