Duplicate column with same name coming after adding a new column

Hello all,
i have added two columns SL,no and Location and performed string operations using for each row activity.but after arranging the columns by using DefaultView.ToTable and writing data into excel i am getting duplicate colmns by same name.Sl.no and Location are coming in A and C columns and also at the end AD and AF columns.i dont want the extra columns coming in the end(also they have same name so cant remove)…pfa the images:

3 4

What operations did u performed?

row(“Location”)=Split(row(“Work Location”).ToString,"-")(0)
row(“Sl no”)=(i+1).ToString

location and sl no. are two new columns added and performing string operation on worklocation in order to get a specific part.
also i have added DefaultView.ToTable(True,“Sl no”,“Name”,…)and all other columns which i want to extract

Ohk and then u write it in different sheet ryt?

yes a new sheet.

Can you share your file?