Courrier-type en anglais - Remerciements pour services rendus (2)

Dear [Mr or Mrs or Sirs], I wanted to write to tell you how grateful I am to you for taking care of [affaire]. I know that you are very busy and I am aware that you spent much of your time on this [projet]. I can assure you that your help has been useful to us and is much appreciated by everyone in [société]. Thank you again. Yours sincerely [votre nom] [votre fonction]