count the duplicate entries with the help of Macro

Maybe :

Sub Test()
  Dim coll As New Collection, arrIn, arrOut, i As Long, p As Long, v1, v2

  arrIn = Sheet1.Range("A1").CurrentRegion.Value
  For i = 2 To UBound(arrIn, 1)
      On Error Resume Next
         coll.Add key:=arrIn(i, 2), Item:=Array(arrIn(i, 2), New Collection)
      On Error GoTo 0
      coll(arrIn(i, 2))(1).Add arrIn(i, 3)
  Next i

  ReDim arrOut(1 To UBound(arrIn, 1), 1 To 4)
  p = 1: arrOut(p, 1) = "SYMBOL": arrOut(p, 2) = "COUNT": arrOut(p, 3) = "SYMBOL": arrOut(p, 4) = "DATE"
  For Each v1 In coll
      arrOut(p + 1, 1) = v1(0)
      arrOut(p + 1, 2) = v1(1).Count
      i = 0
      For Each v2 In v1(1)
          p = p + 1
          i = i + 1
          arrOut(p, 3) = v1(0) & "-" & Application.WorksheetFunction.Roman(i)
          arrOut(p, 4) = v2
      Next v2
  Next v1

  Columns("L:O").ClearContents
  Range("L1").Resize(UBound(arrOut, 1), UBound(arrOut, 2)).Value = arrOut
End Sub