automated text in KPI for the top customer

[Qlikuser09]

FirstSortedValue(([customer Name]), ( Count(sales date), Rank([Customer Name]),1))) this does not work in KPI , to get the top 1 customer .

[Clever_Anjos]

Try with: 

FirstSortedValue([customer Name],aggr(-Count(sales date),[customer Name]))

[Qlikuser09]

thanks, I was able to get the top 3 products, but I wanted to get the top 3 customers for those top products.