Deuxième relance pour impayé (Lettre-type en anglais)

Dear [Mr or Mrs or Sirs], Our letter of [date], in which we informed you that invoice [références] for [montant] due on [date] has not been paid, has remained unanswered. Therefore, we wish to remind you that our terms of trade are [détails], and thank you to give this matter your immediate attention. We look forward to receiving your remittance by return of the post. Yours sincerely [votre nom] [votre fonction]