If the jynx is similar to the junx:
For duplicate channels, try going to MENU, CHANNEL and TV CHANNEL LIST.
You should see a screen with all your channels, including the doubles.
On a channel you don't want, you can press the blue EDIT and then the blue DELETE.
When you exit that screen the selected channels to be deleted are removed. (You can delete multiple channels before exiting).
Also, if you aren't sure which one to delete, 1 channel should have an active display in the corner when selecting it, the other channel will not. And generally, it will be the Nimiq4 that will be the double.