Lock the slicer options

Hi edubcardoso 

You can create a table using Enter data and map that table with the one which has email column.

And use the Email column from new table , that way u'll always see yes and No.

Hi edubcardoso , 

Since in the data for April, you have only "YES" value it is showing one thing in the slicer. If you want to show both "YES" and "No" then you can follow the below steps:
1- create a new table using enter data:(screenshot -> click on enter data -> enter values-> load):

and then click on load.

Step 2:
make a relationship between this new table & "Equal" column:(screenshot) Modelling -> Manage Relationship 

make relationship between Equal column and the new column that is coming from the new table that we created
Step 3: take value in the slicer from the new table.

edubcardoso -> Please hit the thumbs up and mark it as a solution if this helps you. Thanks.