LATE PAYMENT, MODERATE TONE: LETTER 1 (SERVICE)
We thank you for your business and hope to retain you as a valued customer.
Our records indicate that, as of [DATE, ex. June 11], we have not received payment for [STATE TYPE OF SERVICE, ex. accounting] services we rendered to you on [DATE, ex. May 11]. Please consult your records to verify that we have not made a mistake. If payment has already been sent, please disregard this note and accept our thanks.