RANKX and ALLSELECT, trying to rank customers within catagories (with slicers and visual filter)

[BI_Nooby]

Hi,

I'm trying to rank my customers (by sum of sales) within catagories. 
In addition, only showing Top 3 and being able to slice on customer.

My datamodel

My DAX measures:

_SUM = SUMX(Facts, Facts[FACT_VALUES])

Ranking =IF(

ISINSCOPE(Customer[CUSTOMER]),

(RANKX (ALLSELECTED(Customer[CUSTOMER]), CALCULATE(SUM(Facts[FACT_VALUES])),,desc,Dense)))

And my result (which is incorrect)

and another example

I've read several articles, where it suggests the DAX I've written.
But obviously, the ranking isn't going well.

What am I doing wrong?

[Mahesh0016]

@BI_Nooby I hope this helps you!THANK YOU!!

RANK =

CALCULATE(

    RANKX ( ALLSELECTED ( 'Table'[Customer ID] ), [Total Sale],, DESC, DENSE )

)

[BI_Nooby]

Sorry that didn't help. Mind telling me why you think wrapping the RANKX inside a CALCULATE would be the solution?