Charger listbox sans doublon

Sub recap()
  Dim MaCollection As New Collection  ' pour éviter les doublons
  Dim TheDate As Date  ' Déclare les variables.
  Dim Msg, Reponse
  Dim c As Long, n As Long
  Dim LigDeb As Long, LigFin As Long


  Windows("base en projet.xls").Activate


  Range("A1").Select


  Reponse = InputBox("Entrez une date (jj/mm/aaaa)", "Listing contrôle depuis le... ", Sheets("base").Range("A1"))
  If IsDate(Reponse) Then
    TheDate = Reponse
    UserForm3.Label2 = Date - DateDiff("d", TheDate, Now)
    UserForm3.Caption = "Récapitulatif des contrôles depuis le :" & TheDate
    UserForm3.CommandButton2.Caption = "Mise en page du récapitulatif des contrôles depuis le: " & UserForm3.Label2.Caption
    LigFin = Worksheets("base").Range("A65536").End(xlUp).Row + 1
    For n = 1 To LigFin
      If Worksheets("base").Range("A" & n) = CDate(UserForm3.Label2) Then
        LigDeb = n
        Exit For
      End If
    Next n
    If n = LigFin + 1 Then
      MsgBox ("La date n'existe pas!")
      Call recap
    Else
      For n = LigDeb To LigFin
        On Error Resume Next
          MaCollection.Add "item", Worksheets("base").Range("A" & n).Text
          If Err.Number = 0 Then
            With UserForm3.ListBox1
              .AddItem Worksheets("base").Range("a" & n).Text  'date
              .List(.ListCount, 1) = Worksheets("base").Range("b" & n + LigDeb - 1) 'nom
              .List(.ListCount, 2) = Worksheets("base").Range("c" & n + LigDeb - 1) 'immat
            End With
          End If
        On Error GoTo 0
      Next n
      UserForm3.Show
      'UserForm3.CommandButton2_Click
    End If
  Else
    If Reponse = "" Then
      Exit Sub
    Else
      MsgBox ("Format date incorrect!")
      Call recap
    End If


  End If
End Sub