Message dans une box

Option Explicit
Private Sub Worksheet_Change(ByVal c As Range)
    Application.EnableEvents = False
    If c.Row > 2 And c.Column = 1 And c.Count = 1 Then
        If Application.WorksheetFunction.CountIf(Range("A:A"), c.Value) > 1 Then c.ClearContents: MsgBox "Numéro déjà utilisé -- Try again": c.Select
    End If
    If c.Row > 1 And c.Column = 2 And c.Count = 1 Then
        If Right(c, 2) <> 9 Or Len(c) <> 10 Then c.ClearContents: MsgBox "Attention le lot ne correspond à votre produit": c.Select
    End If
    Application.EnableEvents = True
End Sub