Letter requesting waiver of interest on late payment

To Whom It May Concern:

I would like to apologize for my late payment for the services you have rendered.

This is not—and will not be—a common issue. It is against my nature to miss a deadline and I am very embarrassed that it has happened.

Again, I am very sorry for the inconvenience and I hope that we can continue to maintain our professional relationship.

While I understand that late payments incur interest, I humbly ask that you waive the late fee. I have been a patron of your services for many years and have an exemplary track record of punctual payment. Based on my history, please excuse this solitary late payment incident.

Sincerely,
{Sender}