summing duplicated data for specific sheets

hello

I  want  some  help  about  this  code. the  code  collect  the  data  from all  sheets  into  sheet SUMMARY   but  my  problem  if  repeat  some  data   in sheet (sales,pur,returns )

it doesn't  sum duplicat data.I    highlighted  the  wrong values  for   some  repeted data  in sheet (sales,pur,returns )  which  show  in sheet summary and  highlighted  the  repeated  data  from three  sheets 

theses  values are  not  right(100,55,10). the  right  values   should  be 200, 110,21) 

so  it  should  summing  duplicates  values 

Sub CollateData_v2()
  Dim d As Object
  Dim ShList As Variant, a As Variant, vals As Variant
  Dim i As Long, j As Long
  Dim s As String

  Set d = CreateObject("Scripting.Dictionary")
  ShList = Split("stock|sales|pur|returns", "|")
  For j = 0 To UBound(ShList)
    With Sheets(ShList(j))
      a = .UsedRange.Value2
      For i = 2 To UBound(a)
        s = Join(Application.Index(a, i, Array(2, 3, 4)), ";")
        If Len(s) > 2 Then
          If Not d.exists(s) Then d(s) = ";;;"
          vals = Split(d(s), ";")
          vals(j) = a(i, 5)
          d(s) = Join(vals, ";")
        End If
      Next i
    End With
  Next j
  Application.ScreenUpdating = False
  With Sheets("summary")
    .UsedRange.EntireRow.Delete
    With .Range("B2:C2").Resize(d.Count)
      .Value = Application.Transpose(Array(d.Keys, d.Items))
      With .Columns(2)
        .TextToColumns DataType:=xlDelimited, ConsecutiveDelimiter:=False, Semicolon:=True, Comma:=False, Space:=False, Other:=False
        With .Offset(, 4)
          .FormulaR1C1 = "=RC[-4]-RC[-3]+RC[-2]+RC[-1]"
          .Value = .Value
        End With
        .Resize(, 2).EntireColumn.Insert
      End With
      .Columns(1).TextToColumns DataType:=xlDelimited, ConsecutiveDelimiter:=False, Semicolon:=True, Comma:=False, Space:=False, Other:=False
      With .Columns(0)
        .Cells(1).Value = 1
        .DataSeries Rowcol:=xlColumns, Type:=xlLinear, Step:=1
      End With
    End With
    With .Range("A1:I1")
      .Value = Array("item", "BRAND", "TYPE", "MONAFACTURE", "STOCK", "SALES", "PUR", "RETURNS", "BALANCE")
       .Font.Bold = True
  .Interior.Color = RGB(166, 166, 166)
      .EntireColumn.AutoFit
    End With
    With .UsedRange
      .BorderAround xlContinuous
      .Borders(xlInsideVertical).LineStyle = xlContinuous
      .Borders(xlInsideHorizontal).LineStyle = xlContinuous
    End With
  End With
  Application.ScreenUpdating = True
End Sub

any  help  ,please?