The first letter is friendly. We acknowledge that it might have been a mistake or simply it was impossible to pay the invoice and our client needs a kind reminder.If this letter is ignored, we will urge our client to pay in a more intense way with a second and third letter.

Find below ideas on what to say.
First Letter

FAO………………………………………

Dear Sr,

We are contacting you with  reference to our Invoice number ……………… dated on…………………., for the amount of ………………….. euros, due on  ………………… corresponding to  …………………………………..(sales of materials, services provided during ……, etc.).

The reason for this communication is that until now we have not received confirmation of payment of the mentioned invoice, for which we kindly ask you to address the situation as soon as possible.
If you have any question you can contact us / Mr ………. on the following number.

I take the opportunity to thank you for your trust.

(Signature)

SECOND LETTER

FAO………………………………………

Dear Sr,

We are contacting you again with reference to our communication sent on ………. in which we advised you of the pending status of an invoice.

It is invoice Invoice number ……………… dated on…………………., for the amount of ………………….. euros, due on  ………………… .

We kindly urge you to solve the issue with this invoice in a maximum period of 15 days.

If you have any question you can contact us / Mr ………. on the following number.

Thank you in advance for assigning value to our work.

(Signature)

THIRD LETTER

FAO………………………………………

Dear Sr,

We are contacting you again with reference to our previous communications sent on ……….  and again on  in which we urged you to solve the issue with the invoice number ……………… dated on…………………., for the amount of ………………….. euros, due on  ………………… which remain unpaid.

Since we have not received any satisfactory answer from your part, we kindly ask you that you make immediate payment of the invoice to the following bank account………

In case that you are unable to payment the full amount, we are open to negotiate terms of payment that can satisfy both parties and solve the current situation.

If, on the contrary, you choose not to pay and you do not get in contact with us, we will feel obliged to open a file with your name on the Registry of Defaulters and take any legal action that we consider opportune.

Kind Regards,

(Signature)