[DATE, ex. Monday, March 31, 2008]

[NAME, COMPANY AND ADDRESS, ex.
Link Building
XYZ Inc.
1234 First Street
Suite 567
Anycity, Anystate  85245]

Dear [NAME, ex. Link Building],

In reference to your invoice #[INVOICE NUMBER], enclosed, please find our check #[CHECK NUMBER] in the amount of $[AMOUNT].

I do understand that this payment is late and I hope you will accept my apology.  [BRIEFLY STATE REASON, ex. The recent brick-layer strike has adversely but only temporarily affected our liquidity.]  We do, however, look forward to continued business with you.

Sincerely,

[YOUR NAME, ex. Jill Jones]