Modèle de lettre-type (anglais) - Troisième relance pour impayé

Dear [Mr or Mrs or Sirs], We wrote to you on [date] and [date] to remind you that invoice [références] for [montant] due on [date] had not been paid. We regret to notice that these letters have remained unanswered. Therefore, we ask you again to give this matter your immediate attention, so that it can be resolved amicably. We look forward to receiving your remittance no later than [date]. Yours sincerely [votre nom] [votre fonction]