I looked at your Sheets and i need you to specifiy again what is the Source for the Slicer is it a normal Pivot or a Pivot from PowerPivot which is a special Addin

Cause the Approach for powerpivot is different and more complex.
And in your example Sheet you have a normal Pivot

Also in the Source File the user can Only select one Entry is that Correct for the Rea thing too?

Greets
Loki