Index / Match With Multiple Name Ranges

I have two files

Say first file name is X and in work sheet 1 i have used name manager for two columns say "Series" and "Fund name"

Second file name is Y
R7C3 is Fundname of Y file

RC4 is Series Value of Y file

In the row of Y file , C 15 - I want to calculate the formula

Range("C15").FormulaArray = _

"=IF(ISNA(INDEX(Series,MATCH(R7C3&RC4,Fundname&Series,0))=RC4),""NO"",""YES"")"

I am not getting any error but the result is not correct , even for the series which is not there in my file "X" it says "YES"

See my codes below :

Dim colA As Variant
Dim colB As Variant
Dim WksDash As Workbook
Dim Wksfile As Workbook
Dim wksWatch As Worksheet
Dim WksDash2 As Worksheet
Dim Classunion As Variant

[Code] .....